NANOPARTICLES FOR DRUG DELIVERY

Abstract

The invention provides therapeutic magnetic nanoparticles containing a therapeutic agent connected to a magnetic nanoparticle core through a stable functional group and a linker that can be induced to release the therapeutic agent from the core, through hydrolysis of the functional group. Also provided are methods for making nanoparticles, and methods for using nanoparticles.

Claims

1. A therapeutic magnetic nanoparticle, or a salt thereof, comprising a magnetic nanoparticle covalently bonded to one or more -L-D groups wherein; D is a residue of a therapeutic agent; L is a linker -L.sup.1-L.sup.2-; each L.sup.1 is covalently bonded to the magnetic nanoparticle and is independently a branched or unbranched chain or cyclic group or a combination of chain and cyclic groups that comprises 1-200 atoms; and each L.sup.2 is independently a group capable of releasing a therapeutic agent; and wherein L is not capable of undergoing intramolecular cyclization to release the therapeutic agent.

2. The therapeutic magnetic nanoparticle of claim 1, or a salt thereof, comprising a magnetic nanoparticle covalently bonded to one or more -L-D groups wherein D is a residue of a therapeutic agent and L is a linker, wherein: L is -L.sup.1-L.sup.2-; each L.sup.1 is covalently bonded to the magnetic nanoparticle and is independently a branched or unbranched chain or cyclic group or a combination of chain and cyclic groups that comprises 1-50 atoms; and each L.sup.2 is independently a group capable of releasing a therapeutic agent.

3. The therapeutic magnetic nanoparticle of claim 1 or claim 2, wherein L.sup.2 can be hydrolyzed to release the therapeutic agent.

4. The therapeutic magnetic nanoparticle of any one of claims 1-3, wherein L.sup.2 can release the therapeutic agent by application of an alternating electromagnetic field to the magnetic nanoparticle.

5. The therapeutic magnetic nanoparticle of any one of claims 1-4, wherein L.sup.2 is: ##STR00066## W is absent, —O—, —S— or —NR.sup.b—; X is O, S or NR.sup.c; Y is absent, —O—, —S— or —NR.sup.d—; R.sup.b is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; R.sup.c is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; R.sup.d is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; and wherein D together with Y of L.sup.2 or D together with W—C(═X)—Y of L.sup.2 is the moiety: ##STR00067## wherein the moiety is a residue of a therapeutic agent.

6. The therapeutic magnetic nanoparticle of any one of claims 1-5, wherein the atoms that comprise L.sup.1 are selected from carbon, oxygen, nitrogen, sulfur and silicon.

7. The therapeutic magnetic nanoparticle of any one of claims 1-5, wherein the atoms that comprise L.sup.1 are selected from hydrogen, carbon, oxygen, nitrogen, sulfur and silicon.

8. The therapeutic magnetic nanoparticle of any one of claims 1-7, wherein the atoms of L.sup.1 are selected from hydrogen, carbon, oxygen, nitrogen, sulfur and silicon and wherein L.sup.1 does not include an —NH—, —NH.sub.2 or —NHR group wherein R is (C.sub.1-C.sub.6)alkyl.

9. The therapeutic magnetic nanoparticle of any one of claims 1-8, wherein L.sup.1 does not include an —NH—, —NH.sub.2 or —NHR group wherein R is (C.sub.1-C.sub.6)alkyl.

10. The therapeutic magnetic nanoparticle of any one of claims 1-9, wherein L.sup.1 does not include a hydrazone group.

11. The therapeutic magnetic nanoparticle of any one of claims 1-10, wherein L.sup.1 does not include an oxime ether group.

12. The therapeutic magnetic nanoparticle of any one of claim 1 or 3-11, wherein L.sup.1 comprises 2-60 atoms.

13. The therapeutic magnetic nanoparticle of any one of claims 1-11, wherein L.sup.1 comprises 2-30 atoms.

14. The therapeutic magnetic nanoparticle of any one of claims 1-13, wherein L.sup.1 comprises a branched or unbranched chain.

15. The therapeutic magnetic nanoparticle of any one of claims 1-13, wherein L.sup.1 comprises a branched or unbranched chain comprising hydrogen, carbon, oxygen, sulfur or silicon atoms but not nitrogen atoms.

16. The therapeutic magnetic nanoparticle of any one of claims 1-15, wherein L.sup.1 comprises a (C.sub.1-C.sub.15)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene, (C.sub.7-C.sub.15)alkynylene, wherein any (C.sub.1-C.sub.5)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene of L.sup.1 is optionally substituted with one or more halogen.

17. The therapeutic magnetic nanoparticle of any one of claims 1-15, wherein L.sup.1 comprises a (C.sub.1-C.sub.15)alkylene, (C.sub.2-C.sub.15)alkenylene, or (C.sub.2-C.sub.15)alkynylene, wherein any (C.sub.1-C.sub.15)alkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene of L.sup.1 is optionally substituted with one or more halogen.

18. The therapeutic magnetic nanoparticle of any one of claims 1-17, wherein L.sup.1 is covalently bonded to the magnetic nanoparticle through a silicon or sulfur atom.

19. The therapeutic magnetic nanoparticle of any one of claims 1-18, wherein the magnetic nanoparticle further comprises a coating.

20. The therapeutic magnetic nanoparticle of claim 19, wherein the coating comprises gold.

21. The therapeutic magnetic nanoparticle of claim 19, wherein the coating comprises silica.

22. The therapeutic magnetic nanoparticle of any one of claims 1-21, wherein the magnetic nanoparticle comprises iron.

23. The therapeutic magnetic nanoparticle of any one of claims 1-18, wherein the magnetic nanoparticle is an iron oxide nanoparticle coated with silica.

24. The therapeutic magnetic nanoparticle, or a salt thereof, of any one of claims 1-23, wherein each -L-D independently has the following formula I: ##STR00068## wherein: V is —OSi(G).sub.2-, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle; or V is —S—, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle; L.sup.1 is (C.sub.1-C.sub.15)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene, wherein any (C.sub.1-C.sub.15)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene of L.sup.1 is optionally substituted with one or more halogen and wherein the (C.sub.1-C.sub.15)heteroalkylene does not include nitrogen; L.sup.2 is: ##STR00069## W is absent, —O—, —S— or —NR.sup.b—; X is O, S or NR.sup.e; Y is absent, —O—, —S— or —NR.sup.d—; each G is independently —OR.sup.a1, —OR.sup.a2 or (C.sub.1-C.sub.6)alkyl; R.sup.a1 is a covalent bond between the oxygen atom of —OR.sup.a1 and the magnetic nanoparticle; each R.sup.a2 is independently H or (C.sub.1-C.sub.6)alkyl; or two —OR.sup.a2 groups of two adjacent L-D groups together form —O—; R.sup.b is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; R.sup.c is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; R.sup.d is H, (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkenyl or (C.sub.2-C.sub.6)alkynyl; and wherein D together with Y of L.sup.2 or D together with W—C(═Z)—Y of L.sup.2 is a residue of a therapeutic agent.

25. The therapeutic magnetic nanoparticle of claim 24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is optionally coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle optionally coated with silica; or V is —S—, the magnetic nanoparticle is magnetic nanoparticle coated with gold, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle coated with gold.

26. The therapeutic magnetic nanoparticle of claim 24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle coated with silica.

27. The therapeutic magnetic nanoparticle of any one of claims 24-26, wherein the magnetic nanoparticle comprises iron.

28. The therapeutic magnetic nanoparticle of claim 24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle coated with silica.

29. The therapeutic magnetic nanoparticle of claim 24, wherein -L-D has the following formula Ia: ##STR00070## wherein the dashed bond represents a covalent bond to the magnetic nanoparticle.

30. The therapeutic magnetic nanoparticle of claim 24, wherein the magnetic nanoparticle is further coated with silica and wherein -L-D has the following formula Ia: ##STR00071## wherein the dashed bond represents a covalent bond to the magnetic nanoparticle further coated with silica.

31. The therapeutic magnetic nanoparticle of claim 29 or claim 30, wherein the magnetic nanoparticle is an iron oxide nanoparticle.

32. The therapeutic magnetic nanoparticle of any one of claims 24-31, wherein each G is —OR.sup.a1.

33. The therapeutic magnetic nanoparticle any one of claims 24-31, wherein each G is —OR.sup.a2, wherein each —OR.sup.a2 together with another —OR.sup.a2 group on an adjacent L-D group forms an —O—.

34. The therapeutic magnetic nanoparticle any one of claims 24-31, wherein each G is —OR.sup.a1 or —OR.sup.a2, wherein each —OR.sup.a2 together with another —OR.sup.a2 group on an adjacent L-D group form an —O—.

35. The therapeutic magnetic nanoparticle of claim 24, wherein V is —S—, the magnetic nanoparticle is coated in gold, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle coated in gold.

36. The therapeutic magnetic nanoparticle of claim 35, wherein the dashed line represents a covalent bond between —S— and a gold atom of the magnetic nanoparticle coated in gold.

37. The therapeutic magnetic nanoparticle of claim 35 or claim 36, wherein the magnetic nanoparticle is an iron oxide nanoparticle.

38. The therapeutic magnetic nanoparticle of claim 24 or claims 35-37, wherein -L-D has the following formula Ib: ##STR00072## wherein the dashed bonds represent a covalent bond to the magnetic nanoparticle.

39. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.1-C.sub.15)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene, wherein any (C.sub.1-C.sub.15)alkylene, (C.sub.1-C.sub.15)heteroalkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene of L.sup.1 is optionally substituted with one or more halogen and wherein the (C.sub.1-C.sub.15)heteroalkylene

40. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.1-C.sub.15)alkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene, wherein any (C.sub.1-C.sub.15)alkylene, (C.sub.2-C.sub.15)alkenylene or (C.sub.2-C.sub.15)alkynylene of L.sup.1 is optionally substituted with one or more halogen.

41. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.2-C.sub.12)alkylene optionally substituted with one or more halogen.

42. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.2-C.sub.12)alkylene.

43. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.2-C.sub.8)alkylene optionally substituted with one or more halogen.

44. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is (C.sub.2-C.sub.6)alkylene.

45. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is —(CH.sub.2).sub.6—, —(CH.sub.2).sub.3—, or —(CH.sub.2).sub.4—.

46. The therapeutic magnetic nanoparticle of any one of claims 24-38, wherein L.sup.1 is —(CH.sub.2).sub.3— or —(CH.sub.2).sub.6—.

47. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a (C.sub.2-C.sub.12)alkylene optionally substituted with one or more halogen.

48. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a (C.sub.2-C.sub.12)alkylene.

49. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a (C.sub.2-C.sub.8)alkylene optionally substituted with one or more halogen.

50. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a (C.sub.2-C.sub.6)alkylene.

51. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a —(CH.sub.2).sub.6—, —(CH.sub.2).sub.3—, or —(CH.sub.2).sub.4—.

52. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein L.sup.1 comprises a —(CH.sub.2).sub.3— or —(CH.sub.2).sub.6—.

53. The therapeutic magnetic nanoparticle of any one of claims 5-52, wherein W is —O— or —NR.sup.b—.

54. The therapeutic magnetic nanoparticle of any one of claims 5-53, wherein X is O.

55. The therapeutic magnetic nanoparticle of any one of claims 5-54, wherein Y is —O— or —NR.sup.d.

56. The therapeutic magnetic nanoparticle of any one of claims 5-52, wherein L.sup.2 is: ##STR00073##

57. The therapeutic magnetic nanoparticle of any one of claims 5-52, wherein L.sup.2 is: ##STR00074##

58. The therapeutic magnetic nanoparticle of any one of claims 24-57, wherein the portion of formula I as shown in the formula below: ##STR00075## is selected from; ##STR00076##

59. The therapeutic magnetic nanoparticle of any one of claims 1-23, wherein -L-D comprises a group selected from; ##STR00077##

60. The therapeutic magnetic nanoparticle of claim 58, wherein the group covalently bonded to the magnetic nanoparticle through a silicon or sulfur.

61. The therapeutic magnetic nanoparticle of any one of claims 1-47, wherein the residue of a therapeutic is a residue of a prodrug of a therapeutic agent represented by formula IIIe: ##STR00078## wherein Q is —O— or —NH— and R.sup.1a and R.sup.1b together with the remainder of formula IIIe are the residue of the prodrug of the therapeutic agent.

62. The therapeutic magnetic nanoparticle of any one of claims 1-61, wherein the residue of a therapeutic agent is a residue of a chemotherapeutic agent, an antibiotic agent, an antifungal agent, an antiparasitic agent or an antiviral agent or a prodrug thereof.

63. The therapeutic magnetic nanoparticle of any one of claims 1-61, wherein the residue of a therapeutic agent is a residue of a chemotherapeutic agent, an antibiotic agent, an antifungal agent, an antiparasitic agent or an antiviral agent.

64. The therapeutic magnetic nanoparticle of any one of claims 1-61, wherein the residue of a therapeutic agent or prodrug thereof is a residue of Cladribine, Azacitidine, Abraxane, Adcetris, Doxorubicin, Afinitor, Vinblastine, Amifostine, Amifostine, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Bicalutamide, Blemycin, Bortezomib, Cabazitaxel, Irinotecan, Camptothecin, Capecitabine, Temsirolimus, Daunorubicin, Cortisone, Decitabine, Dasatinib, Dexamethasone, Prednisolone, Dexamethasone Acetate, Mitoxantrone, Docetaxel, Hydroxycarbamide, Methylprednisolone, Epirubicin, Curcumin, Estramustine, Eribulin, Etoposide, Everolimus, Raloxifene, Fulvestrant, Floxuridine, Fludarabine, Fluoxymesterone, Gemcitabine, Goserelin, Topotecan, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine, Leuprolide (Leuprorelin), Megestrol, Vinorelbine, Nelarabine, Pentostatin, Octreotide, Paclitaxel, Streptozotocin, Teniposide, Valrubicin, Vorinostat, Zoledronic Acid Cladribine, Azacitidine, Mecaptopurine, Tioguanine, Actinomycin D, Doxorubicin, Anagrelide, Pemetrexed, Vinblastine, Melphalan, Methotrexate, Amifostine, Aminoglutethimide, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Axitinib, Bleomycin, Bosutinib, Folinic Acid (Na or Ca), Leucovorin, Vandetanib, Lenalidomide, Daunorubicin, Crizotinib, Dacarbazine, Decitabine, Dasatinib, Mitoxantrone, Eribulin, Erlotinib, Fludarabine, Pralatrexate, Gefitinib, Gemcitabine, Imatinib, Goserelin, Idarubicin, Lapatinib, Vincristine, Leuprolide, Procarbazine, Methotrexate, Mitomycin, Vinorebine, Nelarabine, Nilotinib, Pentostatin, Octreotide, Pazopanib, Sunitinib, Abraxane, Actinomycin D, Doxorubicin, Afinitor, Exemestane, Carfilzomib, Daunorubicin, Cortisone, Prednisolone, Prednisone, Dexamethasone Acetate, Docetaxel, Methylprednisolone, Epirubicin, Curcumin, Everolimus, Fluoxymesterone, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine, Megestrol, Valrubicin, Mesna, 13-cis-Retinoic Acid, Isotretinoin, Alitretinoin, Melphalan, Tretinoin, Methotrexate, Anastrozole, Bendamustine, Bexarotene, Carmustine, Lomustine, Chlorambucil and Ibritumomab Tiuxetan.

65. The therapeutic magnetic nanoparticle of any one of claims 1-64, wherein the therapeutic nanoparticle further comprises a targeting element.

66. A pharmaceutical composition comprising a therapeutic magnetic nanoparticle as described in any one of claims 1-64, or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

67. A method for administering a therapeutic agent to an animal comprising administering the therapeutic magnetic nanoparticle as described in any one or claims 1-64, or a pharmaceutically acceptable salt thereof, to the animal.

68. A method for treating cancer, a bacterial infection, a fungal infection, a parasitic infection or an antiviral infection in an animal in need thereof that has been administered an effective amount of a therapeutic magnetic nanoparticle as described in any one of claims 1-51, or a pharmaceutically acceptable salt thereof, comprising providing conditions to release the therapeutic agent from the therapeutic magnetic nanoparticle.

69. The method of claim 67 or claim 68, further comprising magnetically targeting the therapeutic magnetic nanoparticle to a specific location in the animal.

70. The method of any one of claims 67-69, further comprising delivering a source of heat to the therapeutic magnetic nanoparticle to hydrolyze the group capable of releasing a therapeutic agent thereby releasing the therapeutic agent from the therapeutic magnetic nanoparticle.

71. The method of any one of claims 67-69, further comprising applying an alternating electromagnetic field to the therapeutic magnetic nanoparticle to hydrolyze the group capable of releasing thereby releasing the therapeutic agent from the therapeutic nanoparticle.

72. The method of any one of claims 67-71, further comprising treating the animal with one or more additional therapeutic agents.

73. The method of claim 72, wherein the additional therapeutic agents are selected from chemotherapeutic agents, antibiotic agents, antifungal agents, antiparasitic agents and antiviral agents.

74. The method of claim 72 wherein one of the additional therapeutic agent is iron oxide nanoparticles.

75. A therapeutic magnetic nanoparticle, or a pharmaceutically acceptable salt thereof as described in any one of claims 1-65 for use in medical therapy.

76. The use of a therapeutic magnetic nanoparticle, or a pharmaceutically acceptable salt thereof as described in any one of claims 1-65 to prepare a medicament for treating cancer, a bacterial infection, a fungal infection, a parasitic infection or an antiviral infection in an animal.

77. A therapeutic magnetic nanoparticle, or a pharmaceutically acceptable salt thereof as described in any one of claims 1-65 for the therapeutic or prophylactic treatment of cancer, a bacterial infection, a fungal infection, a parasitic infection or an antiviral infection.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0195] FIG. 1 illustrates the DLS of SiO.sub.2@Fe.sub.3O.sub.4 NPs in Millipore water.

[0196] FIG. 2 illustrates the ζ-Potential (−46.58±0.47 mV) and mobility (−3.64±0.04) of SiO.sub.2@Fe.sub.3O.sub.4 NPs in Millipore water.

[0197] FIG. 3 illustrates the size distribution (24.1±0.6 nm) of SiO.sub.2@Fe.sub.3O.sub.4 NPs as determined by TEM measurements.

[0198] FIG. 4 illustrates SQUID measurement showing the superparamagnetism of SiO.sub.2@Fe.sub.3O.sub.4 NPs.

[0199] FIG. 5 illustrates the DLS of AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs in Millipore water.

[0200] FIG. 6 illustrates the ζ-Potential (−44.56±2.18 mV) and mobility (−3.48±0.17) of AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs in Millipore water.

[0201] FIG. 7 illustrates the Size distribution (30.4±0.8 nm) of AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs as determined by TEM measurements.

[0202] FIGS. 8A and 8B illustrates the FT-IR of SiO.sub.2@Fe.sub.3O.sub.4NPs.

[0203] FIGS. 9A and 9B illustrates the FT-IR of AO@SiO.sub.2@Fe.sub.3O.sub.4NPs (8).

[0204] FIG. 10 illustrates the TGA of SiO.sub.2@Fe.sub.3O.sub.4 NPs (□) and 8 AO@ SiO.sub.2@Fe.sub.3O.sub.4 NPs (•).

[0205] FIG. 11 illustrates the AMF-induced heating/cooling of 2:1 PBS:acetonitrile (bottom line), SiO.sub.2@Fe.sub.3O.sub.4 NPs (middle line), AMF 5 min on/5 min off sequence (top line).

[0206] FIG. 12 shows the MALDI-TOF of the radical carbocation (Macha, S. F.; et al., J. Am. Soc. Mass Spectrom. 2000, 11, 731-737) of S5 (bottom) and 11 (top) after AMF-induced hydrolysis and release from FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs (9).

[0207] FIG. 13 illustrates the AMF-triggered hydrolysis of pendant functionality (FL=anthracene fluorophore (•); carbamate moiety (darker shaded box in nanoparticle on left); terminal amine residue (lighter shaded box in nanoparticle on right)).

[0208] FIGS. 14A and 14B illustrate TEM images of (14A) SiO.sub.2@Fe.sub.3O.sub.4 NPs used for synthesis of 5 (Scheme 1) and 8 (Scheme 2) and (14B) aminooxy-coated AO@SiO.sub.2@Fe.sub.3O.sub.4NPs (8).

[0209] FIG. 15 illustrates AMF-induced release of anthracene fluorophore from NPs 5 and 6. NPs (7 mg) suspended in 2:1 PBS:acetonitrile (0.75 mL) at pH 7.4 were irradiated with an AMF (501.6 amps, 204 kHz) for 5-minute bursts followed by 5-minute intervals. Vertical axis shows fluorescence intensity normalized to μmol of bound anthracene fluorophore as determined by thermogravimetric analysis.

[0210] FIG. 16 AMF-induced release of 11 from FL@SiO.sub.2@Fe.sub.3O.sub.4: NPs in PBS:acetonitrile were irradiated with an AMF (501.6 amps, 204 kHz) for 5-minute bursts followed by 5-minute intervals; release of 11 from FL@SiO.sub.2@Fe.sub.3O.sub.4: NPs in PBS:acetonitrile were incubated at 37° C. for the indicated time. Vertical axis shows the percent of 11 released as determined by fluorescent measurements; n=3.

[0211] FIG. 17 illustrates the Pulsed AMF-induced hydrolysis of an ester (bar on left), carbamate (bar in the middle) and carbonate (bar on the right) bound to Fe.sub.3O.sub.4 NPs in 2:1 PBS:MeCN. AMF was set at 200 amps and 204 kHz.

[0212] FIG. 18 illustrates the hydrolysis of an ester, carbamate and carbonate bound to Fe.sub.3O.sub.4 NPs without AMF. Functionalized NPs were incubated at 37° C. in 2:1 PBS:MeCN for 20 h.

[0213] FIG. 19 illustrates the suppression of hydrolysis at 37° C. by restricting access to Fe.sub.3O.sub.4 core in 2:1 PBS:MeCN.

[0214] FIG. 20 illustrates a coated magnetic nanoparticle. FIG. 20A illustrates a fully coated magnetic nanoparticle; FIG. 20B illustrates a partially coated magnetic nanoparticle; and FIG. 20C illustrates a partially coated magnetic nanoparticle wherein the coating is non-contiguous (for example spotted).

[0215] FIG. 21 illustrates the hydrolysis and condensation loading of alkoxysilane.

[0216] FIG. 22 illustrates the AMF-induced heating/cooling of 2:1 PBS:acetonitrile (0.75 mL) (bottom line), SiO.sub.2@Fe.sub.3O.sub.4 NPs (7 mg) in 2:1 PBS:acetonitrile (0.75 mL) (middle line), AMF 2 min on/off sequence (top line). AMF conditions: 500 amps, 204 kHz.

[0217] FIG. 23 illustrates the AMF-induced release, as determined by fluorescence measurements, of 11 from FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs in 2:1 PBS:acetonitrile at AMF amperages of 100.7 (n=1), 300.2 (n=1) or 501.6 (n=3). The control, incubated at 37° C. for the indicated time, received no AMF pulses.

[0218] FIG. 24 illustrates AMF-induced release of 11 from FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs during 2 minute (n=1) or 5 minute (n=3) AMF pulses at 501.6 amps versus incubation at 37° C.

DETAILED DESCRIPTION

[0219] Described herein are therapeutic magnetic nanoparticle drug delivery systems that are designed to reduce the problem of payload leakage. Magnetic nanoparticles can be covalently attached to a molecular linker wherein the linker is also covalently bound to a therapeutic agent (e.g., drug) through a functional group such as but not limited to an ester, carbonate or carbamate functional group. It has been discovered that therapeutic magnetic nanoparticles that link a therapeutic agent to a magnetic nanoparticle through a linker and a stable functional group can be induced to release (e.g., hydrolysis of the functional group) the therapeutic agent. In one embodiment the heat generated by the magnetic nanoparticle on AMF exposure induces separation of the therapeutic agent from the linker (e.g., through breaking the bond(s) of the functional group that connects the linker to the therapeutic agent). In one embodiment the functional group is hydrolyzed (e.g., by water or hydroxide ion) thereby releasing the therapeutic agent from the linker. This release mechanism provides a platform for the purposes of drug delivery with both spatial and temporal control.

[0220] Also described herein is an alternative therapeutic magnetic nanoparticle drug delivery system that is designed to reduce the problem of payload leakage. Magnetic nanoparticles can be covalently attached to a molecular linker containing a protected amine wherein the linker is also covalently bound to a therapeutic agent (e.g., drug) through a functional group such as through an ester, carbonate or carbamate functional group. By placing the protected amine at a specified distance from the ester, carbonate or carbamate carbonyl functional group, the protected amine can undergo deprotection followed by intramolecular cyclization, thereby releasing the bound therapeutic agent. In one embodiment the heat generated by the magnetic nanoparticle on AMF exposure induces the deprotection and thereby the subsequent intramolecular cyclization. This release mechanism also provides a platform for the purposes of drug delivery with both spatial and temporal control.

[0221] It is possible to target the therapeutic magnetic nanoparticles to a specific location in a patient's body, e.g., by magnetically guiding the nanoparticles to the target tissue and/or by conjugating appropriate targeting elements (e.g., an antibody fragment, a small molecule ligand of a cellular receptor) to the therapeutic nanoparticle.

[0222] In certain embodiments, the nanoparticles can be magnetically guided to the desired location in the body of the patient. This delivery system provides a method for delivering therapeutic agents including agents that are toxic when administered systemically by allowing for targeting of the drug to a specific location. Thus, this system is particularly useful for delivering drugs that are beneficially delivered to a specific location at a high concentration, e.g., anticancer, antibiotic, antifungal, antiparasitic, and antiviral drugs. An advantage of this delivery system is the delivery of a therapeutic agent to a specific location and the release of the therapeutic agent at a specific time through the selective heating of the magnetic nanoparticle by exposure to an AMF.

[0223] The following definitions are used, unless otherwise described.

Magnetic Nanoparticle.

[0224] Magnetic nanoparticles include any nanoparticles that possess paramagnetic or superparamagnetic (SPM) properties such as those paramagnetic or SPM properties of nanoparticles that comprise iron (iron nanoparticles) which for example include nanoparticles that comprise iron oxide (e.g., iron oxide nanoparticles). The desirable paramagnetic or superparamagnetic (SPM) properties include properties that make the magnetic nanoparticle responsive to a magnetic field (e.g., the magnetic nanoparticles will heat when exposed to an AMF). Thus, magnetic nanoparticles include iron nanoparticles such as nanoparticles comprising iron oxide (e.g., Fe.sub.3O.sub.4, the partially oxidized preparations Fe.sub.2O.sub.3/Fe.sub.3O.sub.4 or the fully oxidized Fe.sub.2O.sub.3). Magnetic nanoparticles also include metal alloys that possess the desired paramagnetic or superparamagnetic (SPM) properties such as those paramagnetic and SPM properties of iron nanoparticles (e.g., iron oxide nanoparticles). Accordingly the term “magnetic nanoparticle” includes nanoparticle alloys, that possess magnetic properties such as but not limited to alloys of iron oxide (for a discussion on magnetic nanoparticle alloys see:Tang, Q., et al., Using Thermal Energy Produced by Irradiation of Mn—Zn Ferrite magnetic Nanoparticles (MZF-NPs) for Heat-Inducible Gene Expression. Biomaterials 2008, 29, 2673-2679 which reference is incorporated herein in its entirety). It is to be understood that the amount of magnetic material (such as iron) in a magnetic nanoparticle can vary as long as the nanoparticle possesses the desired magnetic properties. Magnetic nanoparticles also include magnetic nanoparticles that are coated (e.g., coated magnetic nanoparticles) by another substance or material such as but not limited to gold, graphene or silica. As used herein the term “coated magnetic nanoparticle” includes magnetic nanoparticles wherein the surface of the magnetic nanoparticle is coated (e.g., fully or partially) by the substance or material. It is to be understood the surface of the coated magnetic nanoparticle may be fully coated or partially coated and that when the coated magnetic nanoparticle is partially coated the coating may or may not be contiguous and the coating may be of any shape (e.g., spotted). In one embodiment the surface is at least 1%, at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, at least 90% or completely covered by the substance or material. In one embodiment the core of a coated magnetic nanoparticle is magnetic but the coating may not be magnetic. In one embodiment the magnetic nanoparticle is coated with two or more different coatings. The size of the magnetic nanoparticle can vary. In one embodiment the size of the magnetic nanoparticle is about 1-750 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 1-500 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 1-250 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 1-150 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 1-50 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 5-750 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 5-500 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 5-250 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 5-150 nM in diameter. In one embodiment the size of the magnetic nanoparticle is about 5-50 nM in diameter.

Linker.

[0225] As described herein, the magnetic nanoparticles can be connected to a therapeutic agent through a linker. The linker can be (a) covalently bonded to the magnetic nanoparticle by at least one atom of the linker and (b) covalently bonded to a therapeutic agent at another atom of the linker. Thus, the linker can be covalently bonded to the magnetic nanoparticle or if the magnetic nanoparticle is coated it can be covalently bonded to the coating. It is also to be understood that if a magnetic nanoparticle is coated some of the linkers can be covalently bonded to the coating and some of the linkers can be covalently bonded to the magnetic nanoparticle. For example, the linker can be covalently bonded to the iron oxide magnetic nanoparticle through a silicon atom of the linker. The linker can also be bonded to a coated magnetic nanoparticle, such as a silica coated magnetic nanoparticle through a silicon atom of the linker. The linker can also be bonded to a coated magnetic nanoparticle, such as a gold-coated magnetic nanoparticle. For example, a sulfur atom of a linker can be covalently bonded to a gold atom of a gold-coated magnetic nanoparticle. The linker can be bonded to the magnetic nanoparticle wherein the magnetic nanoparticle is further coated; thus the magnetic nanoparticle is coated but the linker is bonded to the magnetic nanoparticle and not the coating.

[0226] In one embodiment the linker can be covalently bound to the therapeutic agent via a functional group (e.g., ester, amide, carbonate, carbamate, urea, thioester, thioamide, thiocarbonate, thiocarbamate, thiourea) that allows the therapeutic agent to be separated from linker when a bond connecting the functional group to therapeutic agent is broken (e.g., through the hydrolysis of the functional group). In one embodiment the linker is not capable of undergoing intramolecular cyclization. In one embodiment the hydrolysis is facilitated by heat. In one embodiment the hydrolysis is facilitated by AMF.

[0227] In one embodiment the linker can be covalently bound to the therapeutic agent via a functional group (e.g., ester, amide, carbonate, carbamate, urea, thioester, thioamide, thiocarbonate, thiocarbamate, thiourea) that allows the therapeutic agent to be cleaved from the functional group when the linker containing a protected amine undergoes deprotection and intramolecular cyclization as described herein (a protected amine is deprotected to provide a nucleophilic amine that undergoes intramolecular cyclization). The therapeutic agent is generally connected to a carbonyl or thiocarbonyl moiety of the functional group via a labile bond. Thus, when the linker undergoes intramolecular cyclization the bond connecting the therapeutic agent to the carbonyl or thiocarbonyl moiety (for example a bond such as an oxygen, nitrogen or sulfur bonded to either the carbonyl or thiocarbonyl) of the functional group is broken thereby releasing the therapeutic agent from the linker. In one embodiment, the linker, upon heating (e.g., upon AMF irradiation of the attached magnetic NP), undergoes amine deprotection and intramolecular cyclization thereby releasing the therapeutic agent from the linker. The intramolecular cyclization generally occurs through reaction of an amine nitrogen within the linker and the carbon of the carbonyl carbon or thiocarbonyl carbon of the functional group that connects the therapeutic agent to the linker.

[0228] The linkers described herein can vary in length and composition and be branched or non-branched. In one embodiment the linker is a chain (non-cyclic) that is branched or non-branched.

[0229] In one embodiment the linker comprises about 4-50 atoms in the linker. In one embodiment the linker comprises about 4-40 atoms in the linker. In one embodiment the linker comprises about 4-30 atoms in the linker. In one embodiment the linker comprises about 4-20 atoms in the linker. In one embodiment the linker comprises about 4-15 atoms in the linker. In one embodiment the linker comprises about 7-50 atoms in the linker. In one embodiment the linker comprises about 7-40 atoms in the linker. In one embodiment the linker comprises about 7-30 atoms in the linker. In one embodiment the linker comprises about 7-20 atoms in the linker. In one embodiment the linker comprises about 7-15 atoms in the linker. In one embodiment the linker comprises about 6-15 atoms in the linker. In one embodiment the linker comprises about 7-14 atoms in the linker. In one embodiment the linker comprises about 8-14 atoms in the linker. In one embodiment the linker comprises about 9-13 atoms in the linker. In one embodiment any of the above the atoms are independently selected from carbon, nitrogen, oxygen, sulfur and silicon. In one embodiment any of the above the atoms are independently selected from carbon, nitrogen, oxygen, sulfur and silicon provided the linker contains at least one protected amine and one group selected from (C═O) and (C═S). In one embodiment no oxygen, nitrogen, silicon or sulfur are directed bonded (e.g., adjacent) to another oxygen, nitrogen, silicon or sulfur. In one embodiment no oxygen, nitrogen or sulfur are directed bonded (e.g., adjacent) to another oxygen, nitrogen or sulfur. In one embodiment the linker is covalently attached to the magnetic nanoparticle or the coated magnetic nanoparticle by a silicon or sulfur atom. It is to be understood that the atoms that make up the linker include hydrogen atoms to fulfill the valency requirements of any carbon, nitrogen, oxygen, sulfur and silicon atom of the linker. Thus, any of the atoms of the linker are independently selected from carbon, nitrogen, oxygen, sulfur, silicon and hydrogen. In one embodiment the linker comprises about 12-150 atoms in the linker. In one embodiment the linker comprises about 12-120 atoms in the linker. In one embodiment the linker comprises about 12-90 atoms in the linker. In one embodiment the linker comprises about 12-60 atoms in the linker. In one embodiment the linker comprises about 12-45 atoms in the linker. In one embodiment the linker comprises about 21-150 atoms in the linker. In one embodiment the linker comprises about 21-120 atoms in the linker. In one embodiment the linker comprises about 21-90 atoms in the linker. In one embodiment the linker comprises about 21-60 atoms in the linker. In one embodiment the linker comprises about 14-45 atoms in the linker. In one embodiment the linker comprises about 18-45 atoms in the linker. In one embodiment the linker comprises about 21-42 atoms in the linker. In one embodiment the linker comprises about 24-42 atoms in the linker. In one embodiment the linker comprises about 27-39 atoms in the linker. In one embodiment, for any of the above embodiments the linker is the atom range specified.

[0230] It is to be understood that the magnetic nanoparticle may be bonded with multiple linker groups and that some of these groups are adjacent (e.g., in close proximity) to one another. In such situations it is possible that certain groups of the adjacent linkers may interact (e.g., be bonded to each other). One example of this would include linkers which comprise a silicon atom wherein the silicon atoms on adjacent linkers can be connected to one another via a bridging oxygen atom (e.g., —O—).

Therapeutic Agent

[0231] The term “therapeutic agent” includes agents that are useful for the treatment of a disease or a physiological condition in an animal (e.g., a mammal such as a human) and thus includes known drugs. Thus, the term “therapeutic agent” includes but is not limited to known drugs and/or drugs that have been approved for sale in the United States. For example, therapeutic agents include but are not limited to chemotherapeutic agents, antibiotic agents, antifungal agents, antiparasitic agents and antiviral agents. The term “therapeutic agent” also includes “prodrugs” of such therapeutic agents or drugs. The term “therapeutic agent” also includes functional group derivatives of such therapeutic agents or drugs. Such functional group derivatives include for example, but are not be limited to, alcohols of the corresponding ketone of a therapeutic agent. Accordingly, the term “therapeutic agent” includes a therapeutic agent, a prodrug of a therapeutic agent and a functional group derivative of therapeutic agent. It is to be understood that the bond between the therapeutic agent and the linker can be at any suitable atom of the therapeutic agent such as (a) the therapeutic agent itself, (b) the prodrug portion of the prodrug of a therapeutic agent or (c) the functional group derivative portion of the functional group derivative of a therapeutic agent.

[0232] The therapeutic agent can be connected to the linker described herein by the removal of a hydrogen atom from the therapeutic agent (e.g., a residue of a therapeutic agent) which provides the open valency to be connected to the linker. In one embodiment the term —Z-D.sup.1 of formula I can be a residue of a therapeutic agent and the corresponding group H—Z-D.sup.1 can be the corresponding therapeutic agent. In one embodiment the term D of formula I can be a residue of a therapeutic agent and the corresponding group H-D can be the corresponding therapeutic agent. In one embodiment the term D of formula I can be a residue of a prodrug of a therapeutic agent. Thus, one embodiment provides therapeutic agents comprising one or more hydroxyl (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—, —NH(C.sub.1-C.sub.6)alkyl), groups which groups can be connected to the linker as described herein.

In one embodiment D together with Y of L.sup.2 or D together with W—C(═X)—Y of L.sup.2 is the moiety:

##STR00030##

wherein the moiety is a residue of a therapeutic agent. In one embodiment the corresponding therapeutic agent of the residue of the therapeutic agent described in the preceding embodiment is a therapeutic agent of the formula

##STR00031##

[0233] In one embodiment the therapeutic agent is a therapeutic agent (e.g., a drug) or a prodrug of the therapeutic agent.

[0234] In one embodiment the therapeutic agent is a therapeutic agent (e.g., drug) and not a prodrug and not a functional group derivative of the therapeutic agent.

[0235] In one embodiment the therapeutic agent is selected from Cladribine, Azacitidine, Abraxane, Adcetris, Doxorubicin, Afinitor, Vinblastine, Amifostine, Amifostine, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Bicalutamide, Blemycin, Bortezomib, Cabazitaxel, Irinotecan, Camptothecin, Capecitabine, Temsirolimus, Daunorubicin, Cortisone, Decitabine, Dasatinib, Dexamethasone, Prednisolone, Dexamethasone Acetate, Mitoxantrone, Docetaxel, Hydroxycarbamide, Methylprednisolone, Epirubicin, Curcumin, Estramustine, Eribulin, Etoposide, Everolimus, Raloxifene, Fulvestrant, Floxuridine, Fludarabine, Fluoxymesterone, Gemcitabine, Goserelin, Topotecan, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine, Leuprolide (Leuprorelin), Megestrol, Vinorelbine, Nelarabine, Pentostatin, Octreotide, Paclitaxel, Streptozotocin, Teniposide, Valrubicin, Vorinostat, Zoledronic Acid Cladribine, Azacitidine, Mecaptopurine, Tioguanine, Actinomycin D, Doxorubicin, Anagrelide, Pemetrexed, Vinblastine, Melphalan, Methotrexate, Amifostine, Aminoglutethimide, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Axitinib, Bleomycin, Bosutinib, Folinic Acid (Na or Ca), Leucovorin, Vandetanib, Lenalidomide, Daunorubicin, Crizotinib, Dacarbazine, Decitabine, Dasatinib, Mitoxantrone, Eribulin, Erlotinib, Fludarabine, Pralatrexate, Gefitinib, Gemcitabine, Imatinib, Goserelin, Idarubicin, Lapatinib, Vincristine, Leuprolide, Procarbazine, Methotrexate, Mitomycin, Vinorebine, Nelarabine, Nilotinib, Pentostatin, Octreotide, Pazopanib, Sunitinib, Abraxane, Actinomycin D, Doxorubicin, Afinitor, Exemestane, Carfilzomib, Daunorubicin, Cortisone, Prednisolone, Prednisone, Dexamethasone Acetate, Docetaxel, Methylprednisolone, Epirubicin, Curcumin, Everolimus, Fluoxymesterone, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine. Megestrol, Valrubicin, Mesna, 13-cis-Retinoic Acid, Isotretinoin, Alitretinoin, Melphalan, Tretinoin, Methotrexate, Anastrozole, Bendamustine, Bexarotene, Carmustine, Lomustine, Chlorambucil and IbritumomabTiuxetan.

[0236] In one embodiment the therapeutic agent is a chemotherapeutic agent, an antibiotic agent, an antifungal agent, an antiparasitic agent or an antiviral agent or a prodrug thereof.

[0237] In one embodiment the therapeutic agent is a chemotherapeutic agent, an antibiotic agent, an antifungal agent, an antiparasitic agent or an antiviral agent.

[0238] In one embodiment the therapeutic agent has at least one amine (e.g., —NH.sub.2 or —NH(C.sub.1-C.sub.6)alkyl), hydroxy or a thiol group.

[0239] In one embodiment the therapeutic agent has at least one hydroxy (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—, —NH(C.sub.1-C.sub.6)alkyl)) group.

[0240] In one embodiment the therapeutic agent has at least one hydroxy (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—)) group.

[0241] In one embodiment the therapeutic agent has at least one hydroxy or thiol group.

[0242] In one embodiment the therapeutic agent has at least one hydroxy group.

[0243] In one embodiment the therapeutic agent has at least one amine (e.g., —NH.sub.2 or —NH(C.sub.1-C.sub.6)alkyl), hydroxy (—OH) or a thiol group and is attached to the linker through the amine (e.g., —NH.sub.2 or —NH(C.sub.1-C.sub.6)alkyl), hydroxy (—OH) or a thiol group of the therapeutic agent.

[0244] In one embodiment the therapeutic agent has at least one hydroxyl (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—, —NH(C.sub.1-C.sub.6)alkyl)) group and is attached to the linker through the hydroxyl (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—, —NH(C.sub.1-C.sub.6)alkyl)) group of the therapeutic agent.

[0245] In one embodiment the therapeutic agent has at least one hydroxy (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—)) group and is attached to the linker through the hydroxyl (—OH), thiol (—SH) or amine (e.g., primary (—NH.sub.2) or secondary (—NH—)) group of the therapeutic agent.

[0246] In one embodiment the therapeutic agent has at least one hydroxy or thiol (—SH) group and is attached to the linker through the hydroxy (—OH) or thiol (—SH) group of the therapeutic agent.

[0247] In one embodiment the therapeutic agent has at least one hydroxy group (—OH) and is attached to the linker through the hydroxy (—OH) group of the therapeutic agent.

[0248] In one embodiment the therapeutic agent has at least one amine (e.g., primary (—NH.sub.2) or secondary (—NH—)) and is attached to the linker through the amine (e.g., primary (—NH.sub.2) or secondary (—NH—)) group of the therapeutic agent.

[0249] In one embodiment the therapeutic agent has at least one thiol (—SH) group and is attached to the linker through the thiol (—SH) group of the therapeutic agent.

[0250] In one embodiment the therapeutic agent has at least one ketone or aldehyde.

[0251] In one embodiment the therapeutic agent has at least one ketone or aldehyde and is attached to the linker through the ketone or aldehyde group (or the corresponding imine) of the therapeutic agent.

[0252] In one embodiment the therapeutic agent is selected from Cladribine, Azacitidine, Abraxane, Adcetris, Doxorubicin, Afinitor, Vinblastine, Amifostine, Amifostine, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Bicalutamide, Blemycin, Bortezomib, Cabazitaxel, Irinotecan, Camptothecin, Capecitabine, Temsirolimus, Daunorubicin, Cortisone, Decitabine, Dasatinib, Dexamethasone, Prednisolone, Dexamethasone Acetate, Mitoxantrone, Docetaxel, Hydroxycarbamide, Methylprednisolone, Epirubicin, Curcumin, Estramustine, Eribulin, Etoposide, Everolimus, Raloxifene, Fulvestrant, Floxuridine, Fludarabine, Fluoxymesterone, Gemcitabine, Goserelin, Topotecan, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine, Leuprolide (Leuprorelin), Megestrol, Vinorelbine, Nelarabine, Pentostatin, Octreotide, Paclitaxel, Streptozotocin, Teniposide, Valrubicin, Vorinostat and Zoledronic Acid.

[0253] In one embodiment the therapeutic agent is selected from Cladribine, Azacitidine, Mecaptopurine, Tioguanine, Actinomycin D, Doxorubicin, Anagrelide, Pemetrexed, Vinblastine, Melphalan, Methotrexate, Amifostine, Aminoglutethimide, Arabinosylcytosine, Cytarabine, Pamidronic Acid, Nelarabine, Axitinib, Bleomycin, Bosutinib, Folinic Acid (Na or Ca), Leucovorin, Vandetanib, Lenalidomide, Daunorubicin, Crizotinib, Dacarbazine, Decitabine, Dasatinib, Mitoxantrone, Eribulin, Erlotinib, Fludarabine, Pralatrexate, Gefitinib, Gemcitabine, Imatinib, Goserelin, Idarubicin, Lapatinib, Vincristine, Leuprolide, Procarbazine, Methotrexate, Mitomycin, Vinorebine, Nelarabine, Nilotinib, Pentostatin, Octreotide, Pazopanib and Sunitinib.

[0254] In one embodiment the therapeutic agent is selected from Abraxane, Actinomycin D, Doxorubicin, Afinitor, Exemestane, Carfilzomib, Daunorubicin, Cortisone, Prednisolone, Prednisone, Dexamethasone Acetate, Docetaxel, Methylprednisolone, Epirubicin, Curcumin, Everolimus, Fluoxymesterone, Hydrocortisone, Hydrocortone Phosphate, Idarubicin, Ixabepilone, Vincristine, Megestrol, Valrubicin and Mesna.

[0255] In one embodiment the therapeutic agent is selected from 13-cis-Retinoic Acid, Isotretinoin, Alitretinoin, Melphalan, Tretinoin, Methotrexate, Bendamustine, Bexarotene, Chlorambucil, and Ibritumomab Tiuxetan.

[0256] In one embodiment the therapeutic agent is selected from Carmustine, Lomustine, Chlorambucil and Bendamustine.

[0257] Targeting elements (e.g., an antibody fragment, a small molecule ligand of a cellular receptor) can be attached to the therapeutic nanoparticle at any suitable location including the magnetic nanoparticle (directly to nanoparticle or coating of nanoparticle), linker or therapeutic agent by any suitable means.

[0258] “Prodrug” of a therapeutic agent refers to a labile functional group which separates from the active compound during metabolism, systemically, inside a cell, by hydrolysis, enzymatic cleavage, or by some other process (Bundgaard, Hans, “Design and Application of Prodrugs” in A Textbook of Drug Design and Development (1991), P. Krogsgaard-Larsen and H. Bundgaard, Eds. Harwood Academic Publishers, pp. 113-191). Enzymes which are capable of an enzymatic activation mechanism with the prodrug compounds of the invention include, but are not limited to, amidases, esterases, microbial enzymes, phospholipases, cholinesterases, and phosphases. Prodrug moieties can serve to enhance solubility, absorption and lipophilicity to optimize drug delivery, bioavailability and efficacy. A prodrug may include an active metabolite of drug itself.

[0259] “Alkyl” is a straight or branched saturated hydrocarbon. For example, an alkyl group can have 1 to 8 carbon atoms (i.e., (C.sub.1-C.sub.8)alkyl) or 1 to 6 carbon atoms (i.e., (C.sub.1-C.sub.6 alkyl) or 1 to 4 carbon atoms. “Alkylene” refers to an alkyl group having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of the alkyl.

[0260] “Alkenyl” is a straight or branched hydrocarbon with at least one (e.g., one or more) carbon-carbon double bond. For example, an alkenyl group can have 2 to 8 carbon atoms (i.e., C.sub.2-C.sub.8 alkenyl), or 2 to 6 carbon atoms (i.e., C.sub.2-C.sub.6 alkenyl). “Alkenylene” refers to an alkenyl group having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of the alkenyl.

[0261] “Alkynyl” is a straight or branched hydrocarbon with at least one (e.g., one or more) carbon-carbon, triple bond. For example, an alkynyl group can have 2 to 8 carbon atoms (i.e., C.sub.2-C.sub.8 alkyne), or 2 to 6 carbon atoms (i.e., C.sub.2-C.sub.6 alkynyl). “Alkynylene” refers to an alkynyl group having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of the alkyne.

[0262] The term “chain” includes any branched or unbranched arrangement of atoms that are bonded together but are not cyclic. Thus chains include by way of example but are not limited to alkyl, alkenyl, alkynyl and heteroalkyl groups.

[0263] The term “halo” or “halogen” as used herein refers to fluoro, chloro, bromo and iodo.

[0264] The term “carbocycle” or “carbocyclyl” refers to a single saturated (i.e., cycloalkyl) or a single partially unsaturated (e.g., cycloalkenyl, cycloalkadienyl, etc.) all carbon ring having 3 to 7 carbon atoms (i.e. (C.sub.3-C.sub.7)carbocycle). “Carbocyclene” refers to an carbocycle group having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of the carbocycle.

[0265] “Phenylene” refers to a phenyl group having two monovalent radical centers derived by the removal of two hydrogen atoms from two different carbon atoms of the phenyl.

[0266] The term “heteroalkyl” as used herein refers to an alkyl as defined herein, wherein one or more of the carbon atoms of the alkyl are replaced by an O, S, or NR.sub.q, (or if the carbon atom being replaced is a terminal carbon with an OH, SH or NR.sub.q2) wherein each R.sub.q is independently H or (C.sub.1-C.sub.6)alkyl. “Heteroalkylene” refers to a heteroalkyl group having two monovalent radical centers derived by the removal of two hydrogen atoms from a same or two different carbon atoms or an OH, SH or NHR.sub.q of the heteroalkyl.

[0267] The term “heterocyclyl” or “heterocycle” as used herein refers to a single saturated or partially unsaturated ring that has at least one atom other than carbon in the ring, wherein the atom is selected from the group consisting of oxygen, nitrogen and sulfur. Thus, the term includes 3, 4, 5, 6, 7 or 8-membered single saturated or partially unsaturated rings from about 1 to 7 carbon atoms and from about 1 to 4 heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur in the ring. The ring may be substituted with one or more (e.g., 1, 2 or 3) oxo groups and the sulfur and nitrogen atoms may also be present in their oxidized forms. Such rings include but are not limited to azetidinyl, tetrahydrofuranyl or piperidinyl.

[0268] The term “cyclic group” includes any arrangement of atoms that are bonded together that form a cyclic structure. Thus cyclic groups include by way of example but are not limited to carbocycle, phenyl and heterocycle.

[0269] Silica (silicon dioxide (SiO.sub.2)) includes all forms of silica such as amorphous silica, silica gel, mesoporous silica and fumed silica.

[0270] Specific values listed below for radicals, substituents, and ranges are for illustration only; they do not exclude other defined values or other values within defined ranges for the radicals and substituents. It is to be understood that two or more values may be combined.

[0271] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is optionally coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle optionally coated with silica; or V is —S—, the magnetic nanoparticle is magnetic nanoparticle coated with gold, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle coated with gold.

[0272] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle coated with silica.

[0273] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle coated with silica.

[0274] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle.

[0275] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle optionally coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle optionally coated with silica.

[0276] A specific group of compounds of formula I are compounds wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle coated in silica.

[0277] One embodiment provides a therapeutic magnetic nanoparticle linked to a residue of the therapeutic agent with a linker wherein linker includes a protected amine as described in the embodiments E1-E59 below.

E1. A therapeutic magnetic nanoparticle, or a salt thereof, comprising a magnetic nanoparticle covalently bonded to one or more -L-D groups wherein D is a residue of a therapeutic agent and L is a linker that comprises a protected amine wherein the protected amine when deprotected provides an amine which amine is capable of undergoing an intramolecular cyclization.
E2. The therapeutic magnetic nanoparticle of E1, wherein the linker capable of undergoing an intramolecular cyclization is suitable to release a therapeutic agent from the linker upon intramolecular cyclization.
E3. The therapeutic magnetic nanoparticle of E1 or E2, wherein the linker capable of undergoing an intramolecular cyclization can form a 3-8 membered heterocyclic ring upon cyclization.
E4. The therapeutic magnetic nanoparticle of E3, wherein the 3-8 membered ring comprises a group selected from an amide, carbamate, urea, carbamothioate, thioamide, thiocarbamate, thiourea and carbamodithioate.
E5. The therapeutic magnetic nanoparticle of any one of E1-E4, wherein the magnetic nanoparticle further comprises a coating.
E6. The therapeutic of magnetic nanoparticle of any one of E1-E5, wherein the protected amine is an amide, carbamate or urea.
E7. The therapeutic magnetic nanoparticle of any one of E1-E6, wherein the protected amine is an amide, urea or carbamate and the amine of the protected amine is a primary amine or secondary amine.
E8. The therapeutic magnetic nanoparticle of any one of E1-E7, wherein the protected amine is an amide, urea or carbamate and the amine of the protected amine is a primary amine or secondary amine.
E9. The magnetic nanoparticle of E5, wherein the coating is gold.
E10. The magnetic nanoparticle of E5, wherein the coating is silica.
E11. The therapeutic magnetic nanoparticle of any one of E1-E10, wherein the magnetic nanoparticle comprises iron.
E12. The therapeutic magnetic nanoparticle of any one of E1-E11, wherein the magnetic nanoparticle is an iron oxide nanoparticle coated with silica.
E13. The therapeutic magnetic nanoparticle of any one E1-E12, wherein the deprotection of the protected amine can be induced by heating the magnetic nanoparticle.
E14. The therapeutic magnetic nanoparticle of any one of E1-E12, wherein the deprotection of the protected amine occurs prior to the heating the magnetic nanoparticle.
E15. The therapeutic magnetic nanoparticle of any one of E1-E14, wherein the cyclization can be induced by heating the magnetic nanoparticle.
E16. The therapeutic magnetic nanoparticle of any one of E1-E12, wherein deprotection of the protected amine can be induced by application of an alternating electromagnetic field to the magnetic nanoparticle.
E17. The therapeutic magnetic nanoparticle of any one of E1-E12, wherein the deprotection of the protected amine occurs prior to the application of an alternating electromagnetic field to the magnetic nanoparticle.
E18. The therapeutic magnetic nanoparticle of any one of E1-E17, wherein the cyclization can be induced by application of an alternating electromagnetic field to the magnetic nanoparticle.
E19. The therapeutic magnetic nanoparticle of any one of E1-E18, wherein the linker comprises about 4-50 atoms.
E20. The therapeutic magnetic nanoparticle of any one of E1-E18, wherein the linker comprises about 4-20 atoms.
E21. The therapeutic magnetic nanoparticle of E19 or E20, wherein the atoms are independently selected from silicon, carbon, nitrogen, oxygen and sulfur.
E22. The therapeutic magnetic nanoparticle of any one of E1-E21, wherein the linker is covalently bonded to the magnetic nanoparticle through a silicon or sulfur atom.
E23. The therapeutic magnetic nanoparticle of any one of E1-E21, wherein the linker does not include a t-butoxycarbonyl (BOC) protected amine.
E24. The therapeutic magnetic nanoparticle, or a salt thereof, of any one of E1-E23, wherein each -L-D independently has the following formula I:

##STR00032##

wherein

[0278] V is —OSi(G).sub.2-, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle; or V is —S—, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle;

[0279] L.sup.1 is (C.sub.1-C.sub.6)alkylene, (C.sub.1-C.sub.6)heteroalkylene, (C.sub.2-C.sub.6)alkenylene, (C.sub.2-C.sub.6)alkynylene, phenylene or (C.sub.3-C.sub.7)carbocyclene, wherein (C.sub.1-C.sub.6)alkylene, (C.sub.1-C.sub.6)heteroalkylene, (C.sub.2-C.sub.6)alkenylene, (C.sub.2-C.sub.6)alkynylene, phenylene or (C.sub.3-C.sub.7)carbocyclene are optionally substituted with one or more halogen;

[0280] each J is C(R.sup.b).sub.2 wherein one C(R.sup.b).sub.2 of J may be replaced by —O—, —S— or —N(R.sup.e)—;

[0281] (a) W is NR.sup.2, X is CR.sup.cR.sup.d, and n is an integer from 0-5; or

[0282] (b) W is NR.sup.2, X is O, NR.sup.e or S, and n is an integer from 1-5; or

[0283] (c) W is

##STR00033##

X is CR.sup.cR.sup.d, O, NR.sup.e, S or absent, m is an integer from 0-5 and n is an integer from 0-5, wherein the sum of m and n is 0-5;

[0284] Y is O or S;

[0285] Z-D.sup.1 is a residue of a therapeutic agent wherein Z is O, NR.sup.h or S;

[0286] each G is independently —OR.sup.a1, —OR.sup.a2 or (C.sub.1-C.sub.6)alkyl;

[0287] R.sup.a1 is a covalent bond between the oxygen atom of —OR.sup.a1 and the magnetic nanoparticle;

[0288] each R.sup.a2 is independently H or (C.sub.1-C.sub.6)alkyl; or two —OR.sup.a2 groups of two adjacent L-D groups together form —O—;

[0289] each R.sup.b is independently selected from H and (C.sub.1-C.sub.3)alkyl; or two R.sup.b groups together with the carbon to which they are attached form a (C.sub.3-C.sub.7)carbocycle;

[0290] each R.sup.e is independently selected from H and (C.sub.1-C.sub.6)alkyl, and each R.sup.d is independently selected from H and (C.sub.1-C.sub.6)alkyl; or an R.sup.e group and an R.sup.d group together with the carbon to which they are attached form a (C.sub.3-C.sub.7)carbocycle;

[0291] each R.sup.e is independently selected from H and (C.sub.1-C.sub.6)alkyl;

[0292] each R.sup.f is independently selected from H and (C.sub.1-C.sub.6)alkyl; or two R.sup.f groups together with the carbon to which they are attached form a (C.sub.3-C.sub.7)carbocycle;

[0293] R.sup.g is selected from H, (C.sub.1-C.sub.6)alkyl and R.sup.2;

[0294] R.sup.h is selected from H and (C.sub.1-C.sub.6)alkyl;

[0295] each R.sup.2 is independently selected from —C(═O)R.sup.2a, —C(═O)OR.sup.2b, —C(═O)N(R.sup.2c).sub.2, C(═S)R.sup.2a, —C(═S)OR.sup.2b or —C(═S)N(R.sup.2c).sub.2;

[0296] each R.sup.2a is independently selected from H, (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle wherein (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle is optionally substituted with one or more halogen;

[0297] each R.sup.2b is independently selected from H, (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle wherein (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle is optionally substituted with one or more halogen;

[0298] each R.sup.2c is independently selected from H, (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle wherein (C.sub.1-C.sub.10)alkyl, aryl or (C.sub.3-C.sub.7)carbocycle is optionally substituted with one or more halogen; or two R.sup.2c groups together with the nitrogen to which they are attached for a 3-7 membered heterocycle.

E25. The therapeutic magnetic nanoparticle of E24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is optionally coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle optionally coated with silica; or V is —S—, the magnetic nanoparticle is magnetic nanoparticle coated with gold, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle coated with gold.
E26. The therapeutic magnetic nanoparticle of E24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the magnetic nanoparticle coated with silica.
E27. The therapeutic magnetic nanoparticle of any one of E24-E26, wherein the magnetic nanoparticle comprises iron.
E28. The therapeutic magnetic nanoparticle of E24, wherein V is —OSi(G).sub.2-, the magnetic nanoparticle is an iron oxide nanoparticle coated with silica, and the dashed line represents a covalent bond between the oxygen atom of —OSi(G).sub.2- and the iron oxide nanoparticle coated with silica.
E29. The therapeutic magnetic nanoparticle of E24, wherein -L-D has the following formula IIa:

##STR00034##

[0299] wherein the dashed bond represents a covalent bond to the magnetic nanoparticle.

E30. The therapeutic magnetic nanoparticle of E24, wherein the magnetic nanoparticle is further coated with silica and wherein -L-D has the following formula IIa:

##STR00035##

[0300] wherein the dashed bond represents a covalent bond to the magnetic nanoparticle further coated with silica.

E31. The therapeutic magnetic nanoparticle of E29 or E30, wherein the magnetic nanoparticle is an iron oxide nanoparticle.
E32. The therapeutic magnetic nanoparticle of any one of E24-E31, wherein each G is —OR.sup.a1.
E33. The therapeutic magnetic nanoparticle any one of E24-E31, wherein each G is —OR.sup.a2, wherein each —OR.sup.a2 together with another —OR.sup.a2 group on an adjacent L-D group forms an —O—.
E34. The therapeutic magnetic nanoparticle any one of E24-E31, wherein each G is —OR.sup.a1 or —OR.sup.a2, wherein each —OR.sup.a2 together with another —OR.sup.a2 group on an adjacent L-D group form an —O—.
E35. The therapeutic magnetic nanoparticle of E24, wherein V is —S—, the magnetic nanoparticle is coated in gold, and the dashed line represents a covalent bond between —S— and the magnetic nanoparticle coated in gold.
E36. The therapeutic magnetic nanoparticle of E35, wherein the dashed line represents a covalent bond between —S— and a gold atom of the magnetic nanoparticle coated in gold.
E37. The therapeutic magnetic nanoparticle of E35 or E36, wherein the magnetic nanoparticle is an iron oxide nanoparticle.
E38. The therapeutic magnetic nanoparticle of E24 or any one of E35-E37, wherein -L-D has the following formula IIb:

##STR00036##

[0301] wherein the dashed bonds represent a covalent bond to the magnetic nanoparticle.

E39. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is (C.sub.j-C.sub.6)alkylene optionally substituted with one or more halogen.
E40. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is (C.sub.j-C.sub.6)alkylene.
E41. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is (C.sub.2-C.sub.4)alkylene optionally substituted with one or more halogen.
E42. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is (C.sub.2-C.sub.4)alkylene.
E43. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is —(CH.sub.2).sub.2—, —(CH.sub.2).sub.3—, or —(CH.sub.2).sub.4—.
E44. The therapeutic magnetic nanoparticle of any one of E24-E38, wherein L.sup.1 is —(CH.sub.2).sub.3—.
E45. The therapeutic magnetic nanoparticle of any one of E24-E44, wherein:

[0302] (a) W is —NR.sup.2—, X is CR.sup.cR.sup.d, and n is an integer from 0-5; or

[0303] (b) W is —NR.sup.2—, X is O, NR.sup.e or S, and n is an integer from 1-5.

E46. The therapeutic magnetic nanoparticle of any one of E24-E44, wherein:

[0304] (a) W is —NR.sup.2—, X is CR.sup.cR.sup.d, and n is an integer from 0-5; or

[0305] (b) W is —NR.sup.2—, X is O, and n is an integer from 1-5.

E47. The therapeutic magnetic nanoparticle of any one of E24-E44, wherein W is —NR.sup.2—, X is CR.sup.cR.sup.d and n is an integer from 0-5.
E48. The therapeutic magnetic nanoparticle of any one of E24-E47, wherein R.sup.c and R.sup.d are each independently selected from H and methyl.
E49. The therapeutic magnetic nanoparticle of any one of E24-E47, wherein R.sup.c and R.sup.d are each H.
E50. The therapeutic magnetic nanoparticle of any one of E24-E47, wherein R.sup.c and R.sup.d are each methyl.
E51. The therapeutic magnetic nanoparticle of any one of E24-E44, wherein W is —NR.sup.2—, X is O, and n is an integer from 1-5.
E52. The therapeutic magnetic nanoparticle of any one of E24-E51, wherein n is 2, 3 or 4.
E53. The therapeutic magnetic nanoparticle of any one of E24-E52, wherein each J is C(R.sup.b).sub.2.
E54. The therapeutic magnetic nanoparticle of any one of E24-E53, wherein each R.sup.b is independently H or methyl.
E55. The therapeutic magnetic nanoparticle of any one of E24-E54, wherein each R.sup.b is H.
E56. The therapeutic magnetic nanoparticle of any one of E24-E52, wherein J.sub.n is —(CH.sub.2).sub.2—, —(CH.sub.2).sub.3—, —(CH.sub.2).sub.4— or —CH.sub.2CH.sub.2C(Me).sub.2CH.sub.2—.
E57. The therapeutic magnetic nanoparticle of any one of E24-E56, wherein Y is O.
E58. The therapeutic magnetic nanoparticle of E24, wherein the portion of formula I as shown in the formula below:

##STR00037##

[0306] is selected from;

##STR00038##

E59. The therapeutic magnetic nanoparticle of any one of E24-E58 wherein R.sup.2 is not —C(═O)OC(CH.sub.3).sub.3.
E60. The therapeutic magnetic nanoparticle of any one of E24-E58 wherein aryl is phenyl.

Salts

[0307] In cases where compounds are sufficiently basic or acidic, a salt of a therapeutic magnetic nanoparticle as a pharmaceutically acceptable acid or base salt may be appropriate. Examples of pharmaceutically acceptable salts are organic acid addition salts formed with acids which form a physiological acceptable anion, for example, tosylate, methanesulfonate, acetate, citrate, malonate, tartarate, succinate, benzoate, ascorbate, α-ketoglutarate, and α-glycerophosphate. Suitable inorganic salts may also be formed, including hydrochloride, sulfate, nitrate, bicarbonate, and carbonate salts.

[0308] Pharmaceutically acceptable salts may be obtained using standard procedures well known in the art, for example by reacting a sufficiently basic compound such as an amine with a suitable acid affording a physiologically acceptable salt. Alkali metal (for example, sodium, potassium or lithium) or alkaline earth metal (for example calcium) salts of carboxylic acids can also be made.

Administration

[0309] The method of administering the therapeutic magnetic nanoparticle to the desired area for treatment and the dosage may depend upon, but is not limited to, the type and location of the disease material. The size range of the nanoparticles may allow for microfiltration for sterilization. Some methods of administration include intravascular injection, intravenous injection, intraperitoneal injection, subcutaneous injection, and intramuscular injection. The nanoparticles may be formulated in an injectable format (e.g, suspension, emulsion) in a medium such as, for example, water, saline, Ringer's solution, dextrose, dimethylsulfoxide, albumin solution, and oils. The nanoparticles may also be administered to the patient through topical application via a salve or lotion, transdermally through a patch, orally ingested as a pill or capsule or suspended in a liquid or rectally inserted in suppository form. Nanoparticles may also be suspended in an aerosol or pre-aerosol formulation suitable for inhalation via the mouth or nose. Once administered to the patient, delivery of the nanoparticles to the target site may be assisted by an applied static magnetic field due to the magnetic nature of the nanoparticles. Assisted delivery may depend on the location of the targeted tissue. The nanoparticles may also be delivered to the patient using other methods. For example, the nanoparticles may be administered to the patient orally, or may be administered rectally. It is to be understood the therapeutic magnetic nanoparticles described herein may also be useful in diagnostics as well as studies in cells, tissues and animals.

[0310] The invention will now be illustrated by the following non-limiting Examples.

Example 1

General.

[0311] Reagent grade solvents were used for extraction and flash chromatography. Acetonitrile for carbamate synthesis was dried by distillation from CaH.sub.2. All other commercial reagents were used as received without additional purification. The progress of reactions was checked by thin-layer chromatography (TLC, silica gel 60 Å F-254 plates). The plates were visualized first with UV illumination followed by staining using iodine, p-anisaldehyde, phosphomolybdic acid hydrate, or ninhydrin. Column chromatography was performed using silica gel (230-400 mesh). NMR spectra were obtained using a Varian/Agilent 400-MR NMR spectrometer equipped with a 5 mm z-axis gradient AutoX probe operating at the nominal .sup.1H frequency of 399.66 MHz and .sup.13C frequency of 100.49 MHz. All spectra are reported in parts per million (ppm) relative to the residual solvent peak in .sup.1H NMR and the deuterated solvent peak in .sup.13C NMR. High-resolution mass spectra were obtained using a Finnigan LTQ-FT spectrometer (Thermo Electron Corp) in positive detection mode. Fluorescent measurements were taken on a Molecular Devices SpectraMax M5 in fluorescent mode at an excitation of 366 nm and emission wavelength of 408 nm. The fluorescent measurements were taken using a quartz semi-micro VWR Spectrosil spectrophotometer cell with a 10 mm light path. Transmission electron microscopy (TEM) was used to analyze size distribution and morphology of fabricated nanoparticles, including uniformity and thickness of silica coating. For this, ethanol-based nanoparticle dispersions were prepared and drop-casted on commercially available 300 mesh TEM support Cu grids coated with ultra thin carbon films. After ethanol evaporation, samples were transferred to and analyzed using a field emission gun FEI Tecnaci F20 transmission electron microscope operating at the accelerating voltage of 200 kV. DLS and ζ-potential measurements were taken using a Brookhaven Instruments 90Plus Particle Size Analyzer. All measurements were taken using aqueous colloids of the nanoparticles in Millipore water. The alternating magnetic field (AMF) was generated with a Ambrell EasyHeat L1 set at 501.6 amps and 204 kHz using a 5-turn coil.

Synthesis of Linker S4.

[0312] ##STR00039##

[0313] A solution of TBSCl (2.34 g, 15.5 mmol) in dry CH.sub.2Cl.sub.2 (20 mL) was added dropwise over 1 h to a solution of ethylene glycol (8 mL, 143 mmol) and Et.sub.3N (2.80 mL, 19.9 mmol) in dry CH.sub.2Cl.sub.2 (25 mL) at 0° C. and was stirred overnight. The solvent was removed in vacuo and the remaining oil was extracted with hexanes (4×) and the combined extractions were washed twice with sat. NH.sub.4Cl, once with brine and was dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford the mono-TBS protected diol 2-((tert-butyldimethylsilyl)oxy)ethan-1-ol (2.52 g, 92%) as a colorless oil and was used without further purification. R.sub.f 0.59 (1:3, EtOAc:hexanes).

[0314] 1,1′-Carbonyldiimidazole (3.47 g, 21.4 mmol) was added to a solution of the mono-TBS protected diol (2.52 g, 14.3 mmol) and N,N-diisopropylethylamine (3.70 mL, 21.4 mmol) in dry CH.sub.2Cl.sub.2 (48 mL) at 0° C. and was stirred for 6 h. The reaction was washed twice with water and the combined aqueous phases were extracted once with CH.sub.2Cl.sub.2. The combined organic layers were then washed twice with sat. NH.sub.4Cl, once with brine and were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford crude S1 as a colorless oil and was used without further purification. R.sub.f 0.36 (1:3, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.06 (s, 6H), 0.88, (s, 9H), 3.93 (t, J=4.8 Hz, 2H), 4.71 (t, t=4.8 Hz, 2H), 7.06 (s, 1H), 7.42 (s, 1H), 8.13 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.2, 18.4, 25.9, 61.0, 69.4, 117.3, 130.9, 137.3, 149.0.

[0315] The carbamate was synthesized as described in the literature (Heller, S. T.; et al., Angew. Chem., Int. Ed. 2012, 51, 8304-8308). DBU (2.13 mL, 14.3 mmol) was added to a solution of crude S1 (14.3 mmol) in dry MeCN (70 mL) and was stirred for 10 min, then N-methyl-1-aminohex-5-ene (1.60 g, 14.3 mmol) was added and the reaction was stirred overnight. The reaction was then washed twice with sat. NH.sub.4Cl and the combined aqueous layers were extracted three times with EtOAc. The combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 1:3, EtOAc:hexanes) to give a colorless oil S2 (3.56 g, 79% over 3 steps). R.sub.f 0.40 (1:3, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.06 (s, 6H), 0.89 (s, 9H), 1.38 (quin, J=7.4 Hz, 2H), 1.52, (quin, J=7.6 Hz, 2H), 2.07 (q, J=7.2 Hz, 2H), 2.88 (s, 3H), 3.25 (t, J=7.2 Hz, 2H), 3.80 (t, J=5.0 Hz, 2H), 4.13 (t, J=5.0 Hz, 2H), 4.93-5.02 (m, 2H), 5.73-5.84 (m, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.1, 18.5, 26.1, 27.6, 33.6, 34.1, 49.0, 62.0, 66.8, 114.9, 138.7, 156.7; FT-ICR-MS calcd for C.sub.16H.sub.34NO.sub.3Si.sup.+ [M+H].sup.+ m/z 316.2302, found 316.2307.

[0316] TBAF (1 M in THF, 10.6 mL, 10.6 mmol) was added dropwise to a solution of S2 (2.58 g, 8.17 mmol) in dry THF (16 mL) at 0° C. and was stirred overnight. The reaction solution was washed twice with sat. NaHCO.sub.3 and the combined aqueous layers were extracted three times with Et.sub.2O. The combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford crude 2-hydroxyethyl N-(hex-5-en-1-yl)-N-methylcarbamate as a yellow oil and was used without further purification. R.sub.f 0.12 (1:3, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.40 (quin, J=7.8 Hz, 2H), 1.55 (quin, J=7.6 Hz, 2H), 2.08 (q, J=6.8 Hz, 2H), 2.90 (s, 3H), 3.26 (t, J=7.2 Hz, 2H), 3.78-3.82 (q, J=4.4 Hz, 2H), 4.23 (t, J=4.4 Hz, 2H), 4.94-5.02 (m, 2H), 5.74-5.84 (m, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 25.9, 27.4, 33.6, 34.7, 48.9, 62.6, 67.7, 115.0, 138.6, 157.4.

[0317] Methanesulfonyl chloride (728 μL, 9.40 mmol) was added dropwise to a solution of the crude alcohol (8.17 mmol) and triethylamine (1.72 mL, 12.3 mmol) in CH.sub.2Cl.sub.2 (27 mL) at 0° C. and stirred overnight. The reaction was then washed twice with sat. NH.sub.4Cl and the combined aqueous layers were extracted twice with CH.sub.2Cl.sub.2. The combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to give crude 2-(methanesulfonyloxy)ethyl N-(hex-5-en-yl)-N-methylcarbamate as a light yellow oil (2.15 g). R.sub.f 0.36 (major product) & 0.68 (1:1, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3, R.sub.f 0.36) δ 1.37 (quin, J=7.6 Hz, 2H), 1.54 (quin, =7.6 Hz, 2H), 2.07 (q, J=7.2 Hz, 2H), 2.89 (s, 3H), 3.01 (s, 3H), 3.26 (t, J=7.2 Hz, 2H), 4.32-4.34 (m, 2H), 4.39-4.41 (m, 2H), 4.93-5.02 (m, 2H), 5.74-5.81 (m, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3, R.sub.f 0.36) δ 26.1, 27.0, 33.5, 34.1, 37.9, 49.2, 62.8, 68.1, 114.9, 138.6, 155.9.

[0318] K.sub.2CO.sub.3 (1.17 g, 8.47 mmol) was added to a solution of the combined mesyl carbamate products (R.sub.f 0.36 & 0.68) (2.15 g, 7.70 mmol) in DMSO (26 mL), followed by the addition of N-hydroxyphthalimide (2.39 g, 14.6 mmol) and the dark red solution was heated at 75° C. overnight. The yellow solution was cooled to rt and slowly quenched with water and extracted four times with EtOAc. The combined organic phase was washed three times with water, once with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 1:1, EtOAc:hexanes) to give a yellow oil S3 (2.02 g, 71% over 3 steps). R.sub.f 0.55 (1:1, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.35 (quin, J=7.6 Hz, 2H), 1.52 (quin, J=7.6 Hz, 2H), 2.05 (q, J=7.2 Hz, 2H), 2.85 (br s, 3H), 3.24 (t, J=7.2 Hz, 2H), 4.41 (s, 4H), 4.91-5.00 (m, 2H), 5.72-5.82 (m, 1H), 7.72-7.75 (m, 2H), 7.80-7.82 (m, 2H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 26.1, 27.2, 33.5, 34.6, 49.1, 62.8, 76.7, 114.8, 123.7, 129.2, 134.7, 138.7, 156.1, 163.5; FT-ICR-MS calcd for C.sub.18H.sub.23N.sub.2O.sub.5.sup.+ [M+H].sup.+ m/z 347.1601, found 347.1606.

[0319] Hydrazine monohydrate (34 μL, 0.70 mmol) was added to a solution of S3 (258 mg, 0.74 mmol) in CH.sub.2Cl.sub.2 (4 mL) at 0° C. and was stirred for 1 h. The solids were then filtered off and the filter cake was washed with ample CH.sub.2Cl.sub.2. The filtrate was then concentrated in vacuo to afford 7 (154 mg, 96%) as a colorless oil without further purification. R.sub.f 0.24 (1:1, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.36 (quin, J=7.6 Hz, 2H), 1.52 (quin, J=7.6 Hz, 2H), 2.05 (q, J=7.2 Hz, 2H), 2.86 (s, 3H), 3.24 (t, J=7.2 Hz, 2H), 3.80 (t, J=3.6 Hz, 2H), 4.26 (t, J=4.4 Hz, 2H), 4.91-5.00 (m, 2H), 5.42 (br s, 2H), 5.71-5.82 (m, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 26.0, 27.3, 33.5, 34.6, 48.8, 62.9, 74.3, 114.8, 138.7, 156.7; FT-ICR-MS calcd for C.sub.10H.sub.21N.sub.2O.sub.3.sup.+ [M+H].sup.+ m/z 217.1547, found 217.1548.

[0320] Following a related literature example (Sabourault, N.; et al., Org. Lett. 2002, 4, 2117-2119), catalytic PtO.sub.2 and triethoxysilane (131 μL, 0.71 mmol) was added to 7 (153 mg, 0.71 mmol) in a pressure tube. The tube was flushed ti N.sub.2, sealed and heated to 90° C. for 48 h. The reaction solution was cooled to rt and filtered through Celite into a flask flushed with N.sub.2 and the filter cake was washed with ample dry CH.sub.2Cl.sub.2. The filtrate was concentrated in vacuo to afford crude S4 as a light brown oil which was used without further characterization or purification due to its sensitivity to moisture.

Synthesis of Linker S6.

[0321] ##STR00040##

[0322] 2-(Anthracen-9-yl)acetaldehyde (175 mg, 0.79 mmol; (Jiang, H.; et al., Angew. Chem. Int. Ed. 2012, 51, 10271-10274)) was added to a solution of 7 (156 mg, 0.72 mmol) in CH.sub.2Cl.sub.2 (4 mL) and stirred for 1 h. The reaction solution was concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 0:1 to 3:17, EtOAc:CH.sub.2Cl.sub.2 gradient) to give a yellow oil S5 (291 mg, 96%). R.sub.f0.55 (1:19, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.78 (br s, 0.25H), 0.87 (br s, 0.25H), 1.26 (br s, 1.44H), 1.35-1.41 (m, 2H), 1.55-1.63 (m, 2H), 1.92-2.07 (m, 2H), 2.78 (br s, 0.68H), 2.95 (s, 1.91H), 3.14 (br s, 0.46H), 3.22 (br s, 0.46H). 3.30-3.34 (m, 1.33H), 4.26 (dd, J=16.8, 5.4 Hz, 1.78H), 4.49-4.52 (m, 3.48H), 4.68 (d, J=4.4 Hz, 1.31H), 4.88-5.02 (m, 2H), 5.69-5.79 (m, 1H), 6.74 (t, J=5.0 Hz, 0.60H), 7.47-7.57 (m, 4.48H), 8.01-8.05 (m, 2H), 8.19 (d, J=8.4 Hz, 1H), 8.30 (d, J=8.8 Hz, 1H), 8.43 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 25.3, 26.6, 28.7, 33.6, 34.8, 48.8, 64.1, 72.9, 114.9, 124.2, 125.3, 126.3, 127.1, 128.7, 129.4, 130.3, 131.7, 138.7, 150.3, 156.6; FT-ICR-MS calcd for C.sub.26H.sub.31N.sub.2O.sub.3.sup.+ [M+H].sup.+ m/z 419.2329, found 419.2333.

[0323] Linker S6 was synthesized using the procedure described for the synthesis of linker S4.

Synthesis of Linker Precursor 12.3.

2-(Anthracen-9-yl)ethyl pent-4-enoate

[0324] ##STR00041##

[0325] 4-Pentenoic acid (159 μL, 1.56 mmol) and 2-(anthracen-9-yl)ethanol (281 mg, 1.26 mmol) were dissolved in dry CH.sub.2Cl.sub.2 (15 mL) with stirring. DIC (305 μL, 1.95 mmol) was added to the reaction solution followed by cat. DMAP. After 2 h, the white solids were filtered out and the filter cake was washed with CH.sub.2Cl.sub.2. The filtrate was condensed in vacuo and the crude material was purified by column chromatography (SiO.sub.2, 1:1 hexanes:CH.sub.2Cl.sub.2) to give 12.1 (359 mg, 93%) as a yellow oil. R.sub.f 0.36 (1:1 hexanes:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 2.35-2.46 (m, 4H), 3.99 (t, J=8.0 Hz, 2H), 4.50 (t, J=7.8 Hz, 2H), 5.00-5.08 (m, 2H), 5.79-5.88 (m, 1H), 7.46-7.50 (m, 2H), 7.54-7.58 (m, 2H), 8.02 (d, J=8.4 Hz, 2H), 8.38 (d, J=8.8 Hz, 2H), 8.40 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 27.5, 29.0, 33.8, 64.3, 115.7, 124.3, 125.1, 126.2, 127.0, 129.2, 129.4, 130.5, 131.7, 136.8, 173.4.

Allyl 1H-imidazole-1-carboxylate

[0326] ##STR00042##

[0327] N,N-Diisopropylethylamine (5.37 mL, 30.8 mmol) was added to a solution of allyl alcohol (1.21 g, 20.8 mmol) in dry CH.sub.2Cl.sub.2 (69 mL). The solution was cooled to 0° C. and 1,1′-carbonyldiimidazole (5.07 g, 31.2 mmol) was added and the reaction was stirred overnight. The reaction was washed with water (2×40 mL), brine (40 mL) and dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, EtOAc) to give the acyl imidazole intermediate (2.24 g, 71%) as a light yellow oil. R.sub.f 0.51 (EtOAc); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 4.87 (d, J=5.6 Hz, 2H), 5.37 (d, J=10.0 Hz, 1H), 5.44 (d, J=16.8 Hz, 1H), 5.95-6.03 (m, 1H), 7.05 (s, 1H), 7.42 (s, 1H), 8.13 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 68.8, 117.3, 120.6, 130.6, 130.9, 137.3, 148.6.

Allyl (2-(anthracen-9-yl)ethyl) carbonate

[0328] ##STR00043##

[0329] 1,8-Diazabicyclo[5.4.0]undec-7-ene (1.68 mL, 11.2 mmol) was added to a solution of the acyl imidazole intermediate (1.71 g, 11.2 mmol) in dry CH.sub.3CN (56 mL). The reaction solution was stirred for 10 minutes before adding 2-(anthracen-9-yl)ethanol (2.50 g, 11.2 mmol). The reaction was stirred overnight before quenching with sat. NH.sub.4Cl (40 mL). The aqueous phase was extracted with EtOAc (2×40 mL) and the combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 3:1, CH.sub.2Cl.sub.2:hexanes) to give 1.2 (2.33 g, 68%) as yellow crystals. R.sub.f 0.63 (3:1, CH.sub.2Cl.sub.2:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 4.06 (t, J=8.0 Hz, 2H), 4.52 (t, J=8.4 Hz, 2H), 4.69 (d, J=5.6 Hz, 2H), 5.31 (dd, J=10.8, 1.8 Hz, 1H), 5.40 (dd, J=17.6, 1.2 Hz, 1H), 5.93-6.03 (m, 1H), 7.47-7.50 (m, 2H), 7.55-7.59 (m, 2H), 8.02 (d J=8.4 Hz, 2H), 8.35 (d, J=8.8 Hz, 2H), 8.40 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 27.6, 67.4, 68.7, 119.1, 124.1, 125.2, 126.4, 127.2, 128.3, 129.5, 130.5, 131.7, 131.8, 155.3.

2-(Anthracen-9-yl)ethyl 1H-imidazole-1-carboxylate

[0330] ##STR00044##

[0331] N,N-Diisopropylethylamine (408 μL, 2.34 mmol) was added to a solution of 2-(anthracen-9-yl)ethanol (346 mg, 1.55 mmol) in dry CH.sub.2Cl.sub.2 (8 mL), the solution was cooled to 0° C. and 1,1′-carbonyldiimidazole (380 mg, 2.34 mmol) was added. After stirring overnight, the reaction solution was washed with water (2×5 mL), brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, CH.sub.2Cl.sub.2 to 3:2, EtOAc:CH.sub.2Cl.sub.2 gradient) to give the acyl imidazole intermediate (436 mg, 89%) as a pale yellow solid. R.sub.f 0.23 (1:19, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 4.16 (t, J=7.4 Hz, 2H), 4.80 (t, J=7.6 Hz, 2H), 7.02 (s, 1H), 7.31 (s, 1H), 7.50 (t, J=7.6 Hz, 2H), 7.58 (t, J=7.4 Hz, 2H), 8.00 (s, 1H), 8.04 (d, J=8.0 Hz, 2H), 8.33 (d, J=8.8 Hz, 2H), 8.44 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 27.0, 68.0, 117.3, 123.8, 125.3, 126.6, 127.5, 127.9, 129.7, 130.5, 130.8, 131.7, 137.3, 149.0.

2-(Anthracen-9-yl)ethyl allylcarbamate

[0332] ##STR00045##

[0333] 1,8-Diazabicyclo[5.4.0]undec-7-ene (206 μL, 1.38 mmol) was added to a solution of the acyl imidazole intermediate (436 mg, 1.38 mmol) in dry CH.sub.3CN (7 mL). The reaction solution was stirred for 10 minutes before adding allylamine (114 μL, 1.51 mmol). The reaction was stirred overnight before quenching with sat. NH.sub.4Cl (40 mL). The aqueous phase was extracted with EtOAc (2×5 mL) and the combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, CH.sub.2Cl.sub.2 to 2:3, EtOAc:CH.sub.2Cl.sub.2 gradient) to give 1.3 (356 mg, 85%) as pale yellow crystals. R.sub.f 0.72 (1:19, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 3.85 (br s, 2H), 4.00 (t, J=7.8 Hz, 2H), 4.47 (t, J=7.6 Hz, 2H), 4.74 (br s, 1H), 5.13-5.22 (m, 2H), 5.84-5.90 (m, 1H), 7.45-7.49 (m, 2H), 7.53-7.56 (m, 2H), 8.01 (d, J=8.4 Hz, 2H), 8.36 (d, J=8.8 Hz, 2H), 8.39 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 28.1, 43.7, 64.9, 116.3, 124.4, 125.1, 126.2, 126.9, 129.4, 130.6, 131.7, 134.7, 156.7.

Synthesis of SiO.sub.2@Fe.sub.3O.sub.4 NPs.

[0334] The Fe.sub.3O.sub.4 NPs were coated with a thin silica shell using a modified procedure described in the literature (Pinho, S.; et al., ACS Nano 2010, 4, 5339-5349). EMG 304 ferrofluid (1 mL, 233 mg NPs, 8.55×10.sup.16 NPs) was added to Millipore water (98 mL) and was then added to a solution of EtOH (312 mL) and NH.sub.4OH (6.2 mL, 28-30%) with rapid mechanical stirring. Tetraethyl orthosilicate (TEOS) (2.13 mL) was then added to the colloidal suspension and was stirred for 12 h. An aliquot was removed to allow for characterization. The NPs were magnetically separated and the remaining colloidal supernatant was centrifuged at 13,200 RPM for 20 min. The NPs were then washed 5× with EtOH with magnetic separation and centrifugation after each wash. The excess EtOH was then removed by rotary evaporation and the NPs were dried under vacuum for 3 h. The resulting SiO.sub.2@Fe.sub.3O.sub.4 NPs were characterized by IR, TGA, DLS (FIG. 1), ζ-potential (FIG. 2), SQUID (FIG. 4) and TEM (FIG. 3).

SQUID Measurements.

[0335] The magnetic properties of the MNP were measured using a Quantum Design MPMS-5S superconducting quantum interference device (SQUID) magnetometer (in the temperature range from 2 to 400 K). The samples were loaded in a gel capsule and secured inside a standard drinking straw with small holes punched in both the straw and capsule for equalization of pressure and temperature. M(H) data was taken by starting the sample at saturation, 5 T, and then cycling to -5 T and back to 5 T in different step ranges to see the details of the hysteresis. The data was taken using DC Magnetization as to disturb the MNP as little as possible during the measurement (FIG. 4).

Synthesis of AO@SiO.sub.2@Fe.sub.3O.sub.4 and FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs.

[0336] The suspension of SiO.sub.2@Fe.sub.3O.sub.4 NPs was placed under mild vacuum and heated to 60° C. for 8 h. This process was used to remove the catalytic ammonia thus increasing the chances of obtaining a thin organic monolayer on the surface of the NPs. The removal of the ammonia decreased the pH of the solution from 11.7 to 8.8. Then, EtOH (5 mL) was added to S4 or S6 (1.454 mmol) and the solution was added to the NP suspension with rapid mechanical stirring. The mixture was stirred for 20 h. The majority of the AO@SiO.sub.2@Fe.sub.3O.sub.4 or FL@SiO.sub.2@Fe.sub.3O.sub.4NPs were then magnetically separated and the remaining colloidal supernatant was centrifuged at 13,200 RPM for 20 min. The NPs were then washed 5× with EtOH with magnetic separation and centrifugation after each wash. The excess EtOH was then removed by rotary evaporation and the NPs were dried under vacuum for 3 h. The resulting NPs were characterized by IR, TGA, DLS (FIG. 5), ζ-potential (FIG. 6) and TEM (FIG. 7).

Assay of Percent FL Released.

[0337] To determine the percent of 11 released from FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs, the residual amount of S6 remaining on the FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs post AMF exposure was determined as follows. After recording the fluorescence intensity of the last (eighth) AMF pulse, the NPs were magnetically separated and the AMF supernatant was removed. The isolated NPs then were washed 5× with MeCN followed by magnetic separation to remove any non-covalently bound 11. To the washed NPs was added 1 mL of 5% HF in EtOH. The suspension was stirred until all NPs had dissolved resulting in a light yellow solution. The acidic solution was added to a separatory funnel and then basified using sat. aq. NaHCO.sub.3. The basic solution was extracted 3× with Et.sub.2O and the combined extracts were concentrated by rotary evaporation and dried under vacuum. The resulting residue was dissolved in a 2:1 mixture of PBS:MeCN (0.75 mL) at pH 7.4 and the fluorescence was measured. This measured fluorescence intensity was then added to the total fluorescence intensity measured in the supernatant after the final AMF pulse, and the combined intensity was set to 100%. The results from all three experiments were normalized by dividing the fluorescent intensity by the milligrams of FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs used for the experiment.

FT-IR Spectra.

[0338] FT-IR measurements were taken on a Perkin-Elmer Spectrum 100 FT-IR with a universal ATR attachment. All IR spectra underwent ATR correction using Perkin-Elmer software (FIGS. 8A, 8B, 9A and 9B).

TGA.

[0339] TGA measurements were made on a TA Instruments Hi-Res TGA 2950 Thermogravimetric Analyzer using a Pt basket and maintaining a flow of N.sub.2 gas through the oven (FIG. 10). Each TGA experiment was run from 35° C. to 800° C. at a ramp rate of 20° C./min.

AMF Heating of Bulk Solution.

[0340] Temperature measurements were taken with a Neoptix Nomad fitted with a fiber optic temperature sensor. All data was recorded using Neoptix NeoLink software. AMF conditions were set to 501.6 amps and a frequency of 204 kHz. Each AMF pulse lasted for 5 min followed by 5 min of without an AMF for a combined total of 40 min of AMF exposure (FIG. 11). All samples were started at room temperature and were allowed to cool at room temperature; all heating was induced using only an AMF. The control was 0.75 mL of 2:1 PBS:acetonitrile without SiO.sub.2@Fe.sub.3O.sub.4 NPs, which gave a AT of 4.8±0.1° C. with a 5 min AMF pulse. The AT of a 5 min AMF pulse with 7.0 mg of SiO.sub.2@Fe.sub.3O.sub.4 NPs in 0.75 mL 2:1 PBS:acetonitrile was 16.4±0.3° C.

MALDI-TOF Results.

[0341] MALDI-TOF analysis was done on a Voyager DE-Pro MALDI-TOF instrument (PE Biosystems). Spectra were acquired in positive reflectron mode and calibration was achieved by using known peaks from the 2,5-dihydroxybenzoic acid (2,5-DHB) matrix (FIG. 12). Data was analyzed with mMASS data analysis software.

Results and Discussion.

[0342] It has been discovered that AMF can cause the rapid hydrolysis of an otherwise robust chemical linkage, an N,N-disubstituted carbamate. As depicted graphically in FIG. 13, a core-shell Fe.sub.3O.sub.4—SiO.sub.2 NP construct fitted with short chains that terminate with a carbamate-bound fluorophore was engineered. Pulsed AMF irradiation of an aqueous, 37° C. suspension of these NPs buffered at pH 7.4 results in carbamate hydrolysis to release the fluorophore at a rate considerably faster than the limited release observed without irradiation.

[0343] Scheme 1 illustrates covalently tethering a drug to shell-core SiO.sub.2—Fe.sub.3O.sub.4 NPs via carbonate functionality using a linking chain that contains a secondary amine, such as shown by NP assembly 1. Application of an AMF to raise the surrounding temperature resulted in an intramolecular Cyclization via reaction of the amine with the carbonate moiety, as in WO2014/124329. The resultant formation of oxazolidinone 3 would be accompanied by release of the bound substrate R—OH.

##STR00046##

[0344] Studies were conducted to evaluate the thermal responsiveness of a panel of homologous ester and carbonate linkers (Knipp, R. J.; Estrada, R.; Sethu, P.; Nantz, M. H. Tetrahedron 2014, 70, 3422-3429). One study involved carbonate 4 (Scheme 2).

##STR00047##

[0345] A shell-core SiO.sub.2@Fe.sub.3O.sub.4 NPs was prepared using a modified version of the Stober process as reported (Pinho, S.; et al., ACS Nano 2010, 4, 5339-5349). Commercial Fe.sub.3O.sub.4 NPs (EMG 304, FerroTec) with a reported average diameter of 10 nm were silylated to form monodispersed superparamagnetic SiO.sub.2@Fe.sub.3O.sub.4 NPs with a particle size distribution of 24±6 nm and a silica shell thickness of 6-7 nm, as determined by transmission electron microscopy (FIG. 14A). Residual ammonia from the shell application procedure was removed prior to NP functionalization by placing the ethanol/water suspension of SiO.sub.2@Fe.sub.3O.sub.4 NPs under mild vacuum and then heating at 60° C. for 8 h. Removal of the ammonia in this way decreased the pH of the suspension from 11.7 to 8.8. The resultant SiO.sub.2@Fe.sub.3O.sub.4 NPs then were functionalized by adding an ethanolic solution of the triethoxysilane-derived linker obtained from PtO.sub.2-catalyzed (Sabourault, N. et al., Org. Lett. 2002, 4, 2117-2119) hydrosilylation of alkene 4 (Knipp, R. J.; Estrada, R.; Sethu, P.; Nantz, M. H. Tetrahedron 2014, 70, 3422-3429) with (EtO).sub.3SiH to obtain Boc-protected NPs 5 (Scheme 2). The Boc group was cleaved by treatment with trifluoroacetic acid followed by neutralization with triethylamine to unmask the nucleophilic amine needed for the AMF-induced intramolecular cyclization. NPs 6 then were screened in a pulsed AMF experiment for release of the bound anthracene fluorophore.

[0346] A suspension of the free-amine NPs 6 in a 2:1 mixture of PBS:acetonitrile (pH adjusted to 7.4) at room temperature was sequentially pulsed with an AMF for six 5-minute bursts with a delay time of 5 minutes between pulses. Magnetic-assisted sedimentation of the NPs allowed facile measurement of supernatant fluorescence, imparted by the fluorophore released on intramolecular cyclization, at the end of each pulse (FIG. 15). The data clearly show an AMF-induced release of fluorophore, confirmed by MALDI-TOF analysis as 2-(anthracen-9-yl)ethan-1-ol, presumably as a consequence of amine attack onto the proximal carbonate moiety. To test the proposed mechanism of substrate release, the Boc-protected NPs 5, which would be incapable of undergoing the postulated intramolecular cyclization, under identical conditions was examined. Fluorophore release from 5 also occurred in response to AMF irradiation, albeit at a rate slower than the free amine formulation (FIG. 15). This result suggests carbonate cleavage by a route other than oxazolidinone formation, and points toward enhanced hydrolysis as a function of the energy deposited by AMF irradiation. Significant, rapid heating within nanometers of an iron oxide NP surface is known to occur on application of an AMF (Riedinger, A.; et al., T. Nano Lett. 2013, 13, 2399-2406). Another possible mechanism for release of the fluorophore would involve removal of the Boc group followed by intramolecular cyclization. Pulsed AMF irradiation at this concentration of NPs did not significantly increase the temperature of the suspension, as confirmed by measurements taken using a fiber optic temperature sensor (+16.4±0.3° C. from start of AMF pulse to end of AMF pulse, +4° C. from start of first pulse to start of sixth pulse). On examination of the stability of NPs 5 under the same conditions but without AMF irradiation, it was noted the gradual release of 2-(anthracen-9-yl)ethan-1-ol over an hour at 37° C. to ˜50% of the cumulative level achieved by the six 5-minute bursts of AMF irradiation. This finding is noteworthy because dialkylcarbonates are stable to such mild conditions and generally require highly basic conditions for their hydrolysis (e.g., 5M NaOH, MeOH, rt, 3d (Zhang, J.; et al., Macromolecules 2013, 46, 2535-2543). Exposure of carbonate 4 (Scheme 1) to SiO.sub.2@Fe.sub.3O.sub.4 NPs in 2:1 phosphate buffer solution (PBS):acetonitrile at 37° C. resulted in no reaction, even after 24 h exposure. It is possible that the close proximity and the tethered relationship of the carbonate linkage in 5 to the iron oxide core and silica shell enhance, possibly through Lewis acid or hydrogen bonding interactions, respectively, the rate of hydrolysis of an otherwise robust chemical linkage.

[0347] Based on this study additional NPs for an AMF-responsive delivery system that resists hydrolysis at 37° C. and pH 7.4 were examined. One study modified the linker by removing the nucleophilic element and used an N-methyl carbamate linkage to replace the carbonate moiety. Even unsubstituted carbamates are extremely resistant to hydrolysis and typically require treatment with base at elevated temperatures for cleavage (e.g., KOH, diglyme, 200° C.) (Melamed, J. Y.; et al., Bioorg. Med. Chem. Lett. 2010, 20, 4700-4703). A strategy for convenient attachment of substrate to the simplified carbamate-linked NPs, namely oximation was used. Click chemistry reaction of NP-bound aminooxy groups with aldehydes to form oxime ethers can be used as a convenient means for surface functionalization (Biswas, S.; et al., Biomaterials 2011, 32, 2683-2688; Beaudette, T. T et al., J. Am. Chem. Soc. 2009, 131, 10360-10361; Kolb, H. C.; et al., Angew. Chem. Int. Ed. 2001, 40, 2004-2021). Importantly, any newly formed oxime ether linkage would be sufficiently resistant to hydrolysis and thus decrease the risk of a non-AMF induced release (Kalia, J.; Raines, R. Angew. Chem. Int. Ed. 2008, 47, 7523-7526). The combination of these structural alterations is embodied by NP assembly 9 (Scheme 3) in which the anthracene fluorophore probe has been introduced by oximation using (9-anthracenyl)-acetaldehyde (10) (Jiang, H.; et al., Angew. Chem. Int. Ed. 2012, 51, 10271-10274).

##STR00048##

[0348] Aminooxy N-methyl-carbamate 7 (Scheme 3) was loaded onto SiO.sub.2@Fe.sub.3O.sub.4 NPs using the established methodology (Sabourault, N.; et al., Org. Lett. 2002, 4, 2117-2119) to obtain aminooxy NPs 8 (AO@ SiO.sub.2@Fe.sub.3O.sub.4). This functionalization increased the shell thickness by ˜3 nm to afford AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs with a diameter of 30±8 nm as determined by TEM (FIG. 14B). The hydrodynamic diameter of aqueous AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs was measured at 96 nm with a polydispersity of 0.16, roughly similar to the hydrodynamic diameter of the starting SiO.sub.2@Fe.sub.3O.sub.4 NPs at 103 nm with a polydispersity of 0.17. Little change was observed in ζ-potential, where both the SiO.sub.2@Fe.sub.3O.sub.4 and AO@SiO.sub.2@Fe.sub.3O.sub.4 NPs registered ca. −45 mV as aqueous suspensions. Simple mixing of AO@SiO.sub.2@Fe.sub.3O.sub.4 with anthracene aldehyde 10 in aqueous ethanol gave NPs 9 (FL@SiO.sub.2@Fe.sub.3O.sub.4). In an alternate approach, the oximation step was conducted first by reacting anthracene aldehyde 10 with 7 (Scheme 3) followed by hydrosilylation of the oxime ether adduct and then loading onto SiO.sub.2@Fe.sub.3O.sub.4 NPs to obtain 9.

[0349] With the FL@SiO.sub.2@Fe.sub.3O.sub.4 NPs in hand, the AMF-induced hydrolysis of the carbamate linkage was studied by measuring the release of anthracene oxime ether fragment 11 (Scheme 4).

##STR00049##

[0350] The AMF experiments were conducted as described above (2:1 PBS:acetonitrile solution, pH 7.4). As can be seen in FIG. 16, AMF irradiation stimulated a rapid release of substrate from FL@SiO.sub.2@Fe.sub.3O.sub.4. MALDI-TOF analysis confirmed that the oxime ether-anthracene fragment 11 was liberated from the NP formulation on AMF irradiation. Based on fluorescent measurements, 40 minutes of AMF exposure resulted in 67±3% of payload release; longer exposure times did not release additional 11. The switch from carbonate to carbamate dramatically reduced non-AMF release of substrate (FIG. 16)—less than 10% of the payload was released at 37° C. after 40 minutes. The rapid release of the fluorophore fragment on AMF application is quite remarkable in that N,N-dialkyl carbamates are not expected to cleave under these mild conditions (e.g., a previous kinetic study estimates a typical half-life of >550 years at 25° C. and pH 7) (Dittert, L. W.; Higuchi, T. J. Pharm. Sci. 1963, 52, 852-857).

[0351] Uncoated Fe.sub.3O.sub.4 NPs were prepared that incorprotated ester, carbonate and carbamate linkers. Fe.sub.3O.sub.4 NPs were loaded with the alkoxysilane linker following a literature procedure (Galeotti, F.; et al., J. Colloid Interface Sci. 2011, 360, 540-547 and shown in Scheme 5. The alkoxysilane (10 mmol/g NPs) were added to a suspension of Fe.sub.3O.sub.4 NPs in CHCl.sub.3. The mixture was heated to 65° C. for 48 h with mechanical stirring. Upon completion, the functionalized NPs were magnetically separated and the supernatant was decanted. The resulting NPs were washed with CHCl.sub.3 (5×) followed by magnetic separation and decantation. After washing, the NPs were heated to 100° C. for 24 h to induce the final condensation and form a covalent bond between the linker and the iron NP. The loading of the functionalized NPs was determined by thermogravimetric analysis. All fluorescence measurements were taken at an excitation of 360 nm and an emission wavelength of 413 nm in a quartz cuvette. FIG. 17 shows the pulsed AMF-hydrolysis testing while FIG. 18 show hydrolysis without AMF.

##STR00050##

[0352] Fe.sub.3O.sub.4 NPs with different coatings were prepared to test the effect of restricting excess to the Fe.sub.3O.sub.4 core (FIG. 19). Excess polysaccharide, D-lactose or dextran (6 kD), was added to 3.1 (10 mg) in DMSO (1 mL) and the suspension was mixed for 17 h. The NPs were magnetically separated and the supernatant was decanted. The resulting NPs were washed once with DMSO and twice with MeOH before being dried under vacuum.

[0353] Unfunctionalized Fe.sub.3O.sub.4 NPs were coated with a silica shell using the Stöber process (Hui, C.; et al., Nanoscale 2011, 3, 701-705). Briefly, Fe.sub.3O.sub.4 NPs (115 mg) were suspended in Millipore water with sonication, then NH.sub.4OH (25%, 4.4 mL, 28.6 mmol) and EtOH (180 mL) were added to the suspension. With rapid mechanical stirring, tetraethyl orthosilicate (TEOS) (1.76 mL, 7.94 mmol) was added dropwise at rt and reaction was stirred overnight. The SiO.sub.2@Fe.sub.3O.sub.4 NPs were magnetically separated and the supernatant was decanted. The remaining NPs were washed with EtOH (4×) and were dried under vacuum. FIG. 19 shows the hydrolysis of the carbonate linker with these various coatings.

[0354] Therapeutic magnetic nanoparticles with therapeutic agents comprising a ketone or aldehyde group can be readily prepared according Scheme 3 above using chemical steps analogous to those described herein.

[0355] The ketone or aldehyde of the therapeutic agent has been converted to a prodrug of the therapeutic agent as shown in formula IIIa which prodrug is attached to the linker. Accordingly, one embodiment provides a therapeutic agent which is a prodrug of the therapeutic agent and is represented by formula IIIa:

##STR00051##

[0356] wherein R.sup.1a and R.sup.1b together with the remainder of formula IIIa are the prodrug of the therapeutic agent. It is to be understood that the prodrug of formula IIIa represents a therapeutic agent of formula IIIb (wherein R.sup.1a and R.sup.1b and the carbonyl to which they are attached represent a therapeutic agent):

##STR00052##

wherein the ketone or aldehyde of the therapeutic agent of formula IIIb has been condensed with the aminooxy moiety of HO—(CH.sub.2).sub.2—O—NH.sub.2 to arrive at the prodrug of the therapeutic agent of formula IIIa.

[0357] In one embodiment a residue of a therapeutic agent (D or —Z-D.sup.1) is a represented by formula IIIc:

##STR00053##

[0358] wherein R.sup.1a and R.sup.1b together with the remainder of formula IIIc are the residue of the therapeutic agent (D or —Z-D.sup.1).

Example 2. Preparation of Gold NP Linker

[0359] ##STR00054##

Synthesis of Thiol Linker for Loading onto Au@Fe.sub.3O.sub.4 NPs

##STR00055##

4-((tert-Butyldimethylsilyl)oxy)butan-1-ol

[0360] A solution of TBSCl (5.20 g, 34.5 mmol) in dry CH.sub.2Cl.sub.2 (60 mL) was added dropwise over 1 h to a solution of 1,4-butanediol (14.7 mL, 166 mmol) and Et.sub.3N (6.99 mL, 49.8 mmol) in dry CH.sub.2Cl.sub.2 (50 mL) at 0° C. and was stirred overnight. The solvent was removed in vacuo and the remaining oil was extracted with hexanes (4×) and the combined extractions were washed twice with sat. NH.sub.4Cl, once with brine and was dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford crude 4-((tert-butyldimethylsilyl)oxy)butan-1-ol (6.58 g, 93%) as a colorless oil and was used without further purification. R.sub.f 0.44 (1:3, EtOAc:hexanes).

##STR00056##

4-((tert-Butyldimethylsilyl)oxy)butyl methanesulfonate

[0361] Methanesulfonyl chloride (2.87 mL, 37.0 mmol) was added to a solution of crude 4-((tert-butyldimethylsilyl)oxy)butan-1-ol (6.58 g, 32.2 mmol) and Et.sub.3N (6.79 mL, 48.3 mmol) in dry CH.sub.2Cl.sub.2 (107 mL) at 0° C. and was stirred for 2 h. The reaction solution was washed twice with sat. NH.sub.4Cl and the combined aqueous layers were extracted twice with CH.sub.2Cl.sub.2. The combined organic phases were washed once with brine and was dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford 4-((tert-butyldimethylsilyl)oxy)butyl methanesulfonate (9.03 g, 99%) as an orange oil and was used without further purification. R.sub.f 0.52 (1:3, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.04 (s, 6H), 0.88 (s, 9H), 1.62 (quin, J=6.0 Hz, 2H), 1.83 (quin, J=7.2 Hz, 2H), 2.99 (s, 3H), 3.64 (t, J=6.0 Hz, 2H), 4.26 (t, J=6.6 Hz, 2H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.2, 18.5, 26.1, 28.8, 37.6, 62.4, 70.3.

##STR00057##

2-(4-((tert-Butyldimethylsdyl)oxy)butyl)-2,3-dihydro-W-isoindole-1,3-dione

[0362] Phthalimide (8.55 g, 58.1 mmol) was added to a solution of 4-((tert-butyldimethylsilyl)oxy)butyl methanesulfonate (8.64 g, 30.6 mmol) and K.sub.2CO.sub.3 (5.07 g, 36.7 mmol) in DMSO (180 mL) and the solution was heated to 75° C. for 17 h. The reaction was then cooled to rt and was quenched with water. The aqueous solution was extracted with EtOAc (4×) and the combined organic phases were washed with water (3×). The organic phase was then washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford 2-(4-((tert-butyldimethylsilyl)oxy)butyl)-2,3-dihydro-1H-isoindole-1,3-dione (9.27 g, 91%) as white crystals and was used without further purification. R.sub.f 0.59 (1:3, EtOAc:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.03 (s, 6H), 0.87 (s, 9H), 1.55 (quin, J=6.4 Hz, 2H), 1.74 (quin, J=7.4 Hz, 2H), 3.63 (t, J=6.4 Hz, 2H), 3.70 (t, J=7.2 Hz, 2H), 7.65 (dd, J=2.4, 2.8 Hz, 2H), 7.83 (dd, J=1.6, 3.4 Hz, 2H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.1, 18.5, 25.3, 26.1, 30.2, 38.1, 62.7, 123.4, 132.4, 134.0, 168.6.

##STR00058##

(4-Aminobutoxy)(tert-butyl)dimethylsilane

[0363] Hydrazine monohydrate (6.74 mL, 139 mmol) was added to a solution of crude 2-(4-((tert-butyldimethylsilyl)oxy)butyl)-2,3-dihydro-1H-isoindole-1,3-dione (9.27 g, 27.8 mmol) in CH.sub.2Cl.sub.2 (140 mL) at 0° C. and was stirred overnight, allowing the reaction to come to rt. The white precipitate was filtered and the filter cake was washed with ample CH.sub.2Cl.sub.2. The crude solution was concentrated in vacuo to afford (4-aminobutoxy)(tert-butyl)dimethylsilane (3.99 g, 71%) as a light yellow oil and was used without further purification. R.sub.f 0.26 (1:9, MeOH:CH.sub.2Cl.sub.2 with 1% NH.sub.4OH); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.03 (s, 6H), 0.87 (s, 9H), 1.44-1.55 (m, 4H), 1.61 (br s, 2H), 2.68 (t, J=6.8 Hz, 2H), 3.60 (t, J=6.2 Hz); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.1, 18.5, 26.1, 30.4, 30.5, 42.3, 63.3.

##STR00059##

(((3-Bromopropyl)sulfanyl)diphenylmethyl)benzene

[0364] K.sub.2CO.sub.3 (2.28 g, 16.5 mmol) followed by 1,3-dibromopropane (7.61 mL, 75 mmol) was added to a solution of triphenylmethanethiol (4.22 g, 15.3 mmol) in dry THF (75 mL) under N.sub.2. The reaction was refluxed for 24 h before cooling to rt. The reaction solution was washed twice with water, extracted twice with Et.sub.2O, washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The excess 1,3-dibromopropane was distilled off to afford (((3-bromopropyl)sulfanyl)diphenylmethyl)benzene (5.94 g, 98%) as white crystals. R.sub.f 0.54 (1:3, CH.sub.2Cl.sub.2:hexanes); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.81 (quin, J=6.8 Hz, 2H), 2.32 (t, J=6.8 Hz, 2H), 3.32 (t, J=6.8 Hz, 2H), 7.19-7.30 (m, 9H), 7.40-7.44 (m, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 30.5, 31.8, 32.5, 66.9, 126.9, 128.1, 129.8, 144.9.

##STR00060##

12,12,13,13-Tetramethyl-1,1,1-triphenyl-11-oxa-2-thia-6-aza-12-silatetradecane

[0365] (((3-bromopropyl)sulfanyl)diphenylmethyl)benzene (800 mg, 2.01 mmol) was added to a solution of (4-aminobutoxy)(tert-butyl)dimethylsilane (1.02 g, 5.03 mmol) in MeCN (20 mL) and the reaction was heated to 55° C. for 24 h. After cooling to rt, the reaction was quenched with sat. NaHCO.sub.3 and extracted three times with EtOAc. The combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 0:1 to 1:4, MeOH:CH.sub.2Cl.sub.2 with 1% NH.sub.4OH gradient) to give 12,12,13,13-tetramethyl-1,1,1-triphenyl-11-oxa-2-thia-6-aza-12-silatetradecane (852 mg, 82%) as an orange oil. R.sub.f 0.33 (1:4, MeOH:CH.sub.2Cl.sub.2 with 1% NH.sub.4OH); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.04 (s, 6H), 0.88 (s, 9H), 1.51-1.52 (m, 4H), 1.60 (quin, J=7.4 Hz, 2H), 2.17 (t, J=7.0 Hz, 2H), 2.57 (t, J=7.2 Hz, 4H), 3.59 (t, J=6.0 Hz, 2H), 7.17-7.28 (m, 9H), 7.39-7.41 (m, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.1, 18.6, 25.9, 26.2, 28.5, 29.9, 30.7, 48.6, 49.5, 63.2, 66.8, 126.8, 128.1, 129.8, 145.1.

##STR00061##

tert-Butyl N-(4((tert-butyldimethylsiyl)oxy)butyl)-N-(3-((triphenylmethyl)sufanyl) propyl)carbamate

[0366] Boc.sub.2O (348 mg, 1.60 mmol) was added to a solution of 12,12,13,13-tetramethyl-1,1,1-triphenyl-11-oxa-2-thia-6-aza-12-silatetradecane (754 mg, 1.45 mmol) and Et.sub.3N (224 μL, 1.60 mmol) in CH.sub.2Cl.sub.2 (5 mL) at 0° C. After 3 h, the reaction solution was washed twice with sat. NH.sub.4Cl and the aqueous phase was extracted twice with CH.sub.2Cl.sub.2. The combined organic phases were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford crude tert-butyl N-(4((tert-butyldimethylsiyl)oxy)butyl)-N-(3-((triphenylmethyl)sufanyl)propyl)carbamate as an orange oil and was used without further purification. R.sub.f 0.81 (1:19, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 0.03 (s, 6H), 0.88 (s, 9H), 1.39 (br s, 4H), 1.45 (br s, 2H), 1.52 (s, 9H), 2.13 (t, J=7.4 Hz, 2H), 3.05 (br s, 4H), 3.58 (t, J=6.0 Hz, 2H), 7.18-7.29 (m, 9H), 7.39-7.41 (m, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ −5.1, 18.5, 25.9, 26.2, 27.6, 28.6, 29.6, 30.3, 46.5, 47.1, 63.1, 66.8, 79.3, 126.8, 128.1, 129.8, 145.1, 155.6.

##STR00062##

tert-Butyl N-(4-hydroxybutyl)-N-(3-((triphenylmethyl)sulfanyl)propyl)carbamate

[0367] TBAF (1.89 mL of 1 M solution in THF, 1.89 mmol) was added to a solution of crude tert-butyl N-(4((tert-butyldimethylsiyl)oxy)butyl)-N-(3-((triphenylmethyl)sufanyl) propyl)carbamate (1.45 mmol) in dry THF (3 mL) at 0° C. and the reaction was stirred overnight, allowing the reaction to warm to rt. Upon completion, the reaction was washed twice with sat. NaHCO.sub.3 and the combined aqueous phases were extracted three times with Et.sub.2O. The combined organic layers were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 3:7, EtOAc:CH.sub.2Cl.sub.2) to give tert-butyl N-(4-hydroxybutyl)-N-(3-((triphenylmethyl)sulfanyl)propyl)carbamate (453 mg, 62% over 2 steps) as a light yellow oil. R.sub.1 0.52 (3:7, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.40 (s, 9H), 1.47-1.51 (m, 4H), 1.58 (quin, J=7.6 Hz, 2H), 3.08 (br s, 4H), 3.63 (t, J=6.0 Hz, 2H), 7.19-7.30 (m, 9H), 7.41-7.43 (m, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 24.8, 28.2, 28.6, 29.5, 29.7, 46.6, 46.9, 62.6, 66.8, 79.5, 126.8, 128.0, 129.7, 145.0, 155.7.

##STR00063##

4-(((tert-Butoxy)carbonyl)((3-((triphenylmethyl)sulfanyl)propyl))amino) butyl 1H-imidazole-1-carboxylate

[0368] 1,1′-Carbonyldiimidazole (214 mg, 1.32 mmol) was added to a solution of tert-butyl N-(4-hydroxybutyl)-N-(3-((triphenylmethyl)sulfanyl)propyl) carbamate (444 mg, 0.88 mmol) and (i-Pr).sub.2NEt (228 μL, 1.32 mmol) in dry CH.sub.2Cl.sub.2 (3 mL) at 0° C. and was stirred overnight. The reaction solution was washed twice with water and extracted once with CH.sub.2Cl.sub.2. The combined organic layers were washed twice with sat. NH.sub.4Cl, once with brine, were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to afford crude 4-(((tert-butoxy)carbonyl)((3-((triphenylmethyl)sulfanyl)propyl)) amino) butyl 1H-imidazole-1-carboxylate (517 mg, 98%) as a light yellow oil and was used without further purification. R.sub.f 0.50 (3:7, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.42 (s, 9H), 1.59 (br s, 4H), 1.76 (quin, J=6.8 Hz, 2H), 2.18 (t, J=7.4 Hz, 2H), 3.11 (br s, 4H), 4.42 (t, =6.6 Hz, 2H), 7.08 (s, 1H), 7.20-7.31 (m, 9H), 7.42-7.44 (m, 7H), 8.15 (s, 1H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 24.6, 25.9, 28.2, 28.5, 29.4, 46.5 (2 C's), 66.8, 68.1, 79.6, 117.2, 126.7, 128.0, 129.7, 130.8, 137.2, 144.9, 148.8, 155.5.

##STR00064##

2-(2-(((4-(((tert-Butoxy)carbonyl)((3-((triphenylmethyl)sulfanyl)propyl))amino) butoxy)carbonyl)oxy)ethoxy)-2,3-dihydro-1H-isoindole-1,3-dione

[0369] DBU (129 μL, 0.86 mmol) was added to a solution of crude tert-butyl N-(4-hydroxybutyl)-N-(3-((triphenylmethyl)sulfanyl)propyl)carbamate (517 mg, 0.86 mmol) in dry MeCN (4 mL). After stirring for 10 min, 2-(2-hydroxyethoxy)-2,3-dihydro-1H-isoindole-1,3-dione (178 mg, 0.86 mmol) was added and the reaction was stirred overnight. Upon completion, the reaction was washed twice with sat. NH.sub.4Cl and the combined aqueous layers were extracted three times with EtOAc. The combined organic layers were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (SiO.sub.2, 3:17, EtOAc:CH.sub.2Cl.sub.2) to give 2-(2-(((4-(((tert-butoxy)carbonyl)((3-((triphenylmethyl)sulfanyl) propyl))amino)butoxy)carbonyl)oxy) ethoxy)-2,3-dihydro-1H-isoindole-1,3-dione (350 mg, 55% over 2 steps) as a colorless oil. R.sub.f 0.75 (3:17, EtOAc:CH.sub.2Cl.sub.2); NMR (400 MHz, CDCl.sub.3) δ 1.40 (s, 9H), 1.46-1.64 (m, 6H), 2.15 (t, J=7.4 Hz, 2H), 3.06 (br s, 4H), 4.14 (t, J=6.4 Hz, 2H), 4.43-4.48 (m, 4H), 7.18-7.29 (m, 9H), 7.39-7.42 (m, 6H), 7.73-7.76 (m, 2H), 7.81-7.85 (m, 2H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 24.6, 26.1, 28.2, 28.6, 29.5, 46.5, 46.6, 65.2, 68.1, 75.6, 79.5, 123.8, 126.8, 128.0, 129.0, 129.7, 134.7, 145.0, 155.1, 155.5, 163.5.

##STR00065##

N-(4-(((2-(aminooxy)ethoxy)carbonyl)oxy)butyl)-N-((tert-butoxy)carbonyl)-3-((triphenylmethyl)sulfanyl)propan-1-amine

[0370] Hydrazine monohydrate (51 μL, 1.04 mmol) was added to a solution of 2-(2-(((4-(((tert-butoxy)carbonyl)((3-((triphenylmethyl)sulfanyl)propyl))amino)butoxy)carbonyl) oxy)ethoxy)-2,3-dihydro-1H-isoindole-1,3-dione (154 mg. 0.21 mmol) in CH.sub.2Cl.sub.2 at 0° C. and stirred for 2 h. When complete, the white precipitate was removed by filtration and the filter cake was washed with ample CH.sub.2Cl.sub.2. The filtrate was concentrated in vacuo to afford 28 (127 mg, 100%) as a colorless oil and did not require further purification. R.sub.f 0.52 (1:3, EtOAc:CH.sub.2Cl.sub.2); .sup.1H NMR (400 MHz, CDCl.sub.3) δ 1.38 (s, 9H), 1.48-1.62 (m, 6H), 2.14 (t, J=7.4 Hz, 2H), 3.05 (br s, 4H), 3.85 (t, J=4.6 Hz, 2H), 4.12 (t, =6.4 Hz, 2H), 4.33 (t, J=4.4 Hz, 2H), 5.51 (br s, 2H), 7.18-7.21 (m, 3H), 7.25-7.29 (m, 6H), 7.39-7.41 (m, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3) δ 24.7, 26.2, 27.5, 28.6, 29.5, 46.7 (2 C's), 65.5, 66.8, 68.0, 73.4, 79.5, 126.8, 128.0, 129.7, 145.0, 155.5, 155.6.

[0371] All publications, patents and patent applications cited herein are incorporated herein by reference. While in the foregoing specification this invention has been described in relation to certain embodiments thereof, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein may be varied considerably without departing from the basic principles of the invention.

[0372] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g, “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0373] Embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.