Method for improving the oral bioavailability of a drug
11633484 · 2023-04-25
Assignee
Inventors
Cpc classification
C07H15/18
CHEMISTRY; METALLURGY
A61K47/549
HUMAN NECESSITIES
International classification
C07H15/18
CHEMISTRY; METALLURGY
C07H15/26
CHEMISTRY; METALLURGY
Abstract
The invention is in the field of medical sciences. It provides new pharmaceutical methods and preparations. In particular, the invention relates to a method for increasing the oral bioavailability of drugs. The invention also provides new compositions comprising a drug covalently attached to a saccharide as in formula (I) below. More in particular, the invention relates to a method for increasing the oral bioavailability of a drug by covalently attaching a sugar-linked, N-substituted or unsubstituted carbamoylalkylidene moiety to a hydroxyl or thiol group of a drug, wherein the substituents are as defined in the claims. ##STR00001##
Claims
1. A compound of formula (I) ##STR00030## wherein Sugar is a beta-linked monosaccharide, wherein the Sugar is glucose or galactose, wherein optionally one or more OH groups are replaced by a group R4; wherein R4 is selected from the group consisting of C.sub.1-C.sub.6 alkoxy, chlorine, fluorine, cyano, CF.sub.3, NH.sub.2, C.sub.1-C.sub.6 alkyl-NH, C.sub.1-C.sub.6 dialkyl-N, C.sub.1-C.sub.6 cycloalkyl-N, C.sub.1-C.sub.6 alkyl-C(O)NH, C.sub.1-C.sub.6 alkyl-C(O)(C.sub.1-C.sub.6 alkyl)-N, HC(O)(C.sub.1-C.sub.6 alkyl)-N, C.sub.1-C.sub.6 alkyl-O—C(O)NH, C.sub.1-C.sub.6 alkyl-O—C(O)(C.sub.1-C.sub.6 alkyl)-N, and C.sub.1-C.sub.6 alkyl-O—C(O)—O; R1 is selected from the group consisting of H, C.sub.1-CH.sub.6 alkyl, C.sub.2-CH.sub.6 alkenyl, C.sub.2-C.sub.6 alkynyl, —R5—O—R7, —R5—S—R7, —R6—C(O)—R7, —R6—C(O)—O—R7, —R5—SO.sub.2—R7, —R5—SO.sub.2—NR7R8, C.sub.3C.sub.7 cycloalkyl, C.sub.4-C.sub.7 cycloalkenyl, a 4 to 7 membered heterocycle, aryl and (C.sub.1-C.sub.3 alkyl)-aryl; wherein R5 is C.sub.2 or C.sub.3 alkyl, R6 is C.sub.1-C.sub.3 alkyl, R7 and R8 are independently hydrogen or C.sub.1-C.sub.3-alkyl; and wherein the C.sub.3-C.sub.7 cycloalkyl, C.sub.4-C.sub.7 cycloalkenyl, a 4 to 7 membered heterocycle, aryl and (C.sub.1-C.sub.3alkyl)-aryl groups can be optionally substituted by R9, wherein R9 is selected from the group consisting of C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, chlorine, fluorine, cyano, CF.sub.3, amine, amide, carbamate and —C(O)O—(C.sub.1-C.sub.4-alkyl); R2 and R3 are both H, or one of R2 and R3 is H and the other is C.sub.1-C.sub.6 alkyl; X-DM represents a drug moiety wherein X is O or S; or a pharmaceutically acceptable salt thereof.
2. The compound according to claim 1, wherein R1 is selected from the group consisting of C.sub.1-C.sub.4 alkyl, C.sub.2-C.sub.4 alkenyl, —R5—O—R7, —R5—S—R7, —R6—C(O)—R7, —R6—C(O)—O—R7, —R5—SO.sub.2—R7, —R5—SO.sub.2—NR7R8, C.sub.3-C.sub.7 cycloalkyl, wherein C.sub.3-C.sub.7 cycloalkyl is optionally substituted by one or two fluorine; pyranyl, tetrahydrofuranyl and benzyl, wherein R5 is C.sub.2 or C.sub.3 alkyl, R6 is C.sub.1-C.sub.3 alkyl, R7 and R8 are independently hydrogen or C.sub.1-C.sub.3-alkyl.
3. The compound according to claim 2, wherein R1 is selected from the group consisting of C.sub.1-C.sub.4 alkyl, allyl, methoxyethyl, ethoxyethyl, methylthioethyl, C.sub.3-C.sub.6 cycloalkyl, wherein the C.sub.3-C.sub.6 cycloalkyl can be optionally substituted by one or two F, pyranyl, tetrahydrofuranyl, benzyl, carbethoxymethyl, carbomethoxyethyl and methanesulfonyl ethyl.
4. The method according to claim 1, wherein the compound has the structure ##STR00031## wherein R1, X and DM are as defined above and R4a, R4b, R4c, R4d and R4e are independently selected from OH, F and H with the following provisions: at least two of R4a, R4b, R4c, R4d and R4e are OH whereas R4c and R4d cannot both be OH.
5. The method according to any one of the preceding claims wherein R2 and R3 are both H.
6. The method according to any one of the preceding claims, wherein the drug moiety is selected from the group consisting of quetiapine, montelukast, venlafaxine, mesalazine, desvenlafaxine, metoprolol, paliperidone, buprenorphine, morphine, ganciclovir, tapentadol, rotigotine, abiraterone, acetaminophen, saxagliptin, fulvestrant, afimoxifene, testosterone, simvastatin, tolterodine, tramadol, atenolol, naloxone, nabilone, metaraminol, dihydroartemisinin, orciprenaline, labetalol, kalydeco, azacitidine, niclosamide, tetrahydrocannabinol, raloxifene, propofol, gemcitabine, cannabidiol, carvedilol, edavarone, cytarabine, dasatinib, perrilyl alcohol, butorphanol and bazedoxifene.
7. Pharmaceutical composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier.
8. A method for increasing the oral bioavailability of a drug HX-DM. wherein HX represents an OH or SH functional group, comprising the step of linking a sugar-carbamoylalkylidene unit of formula (II) ##STR00032## wherein Sugar, R1, R2 and R3 are as defined in claim 1 and wherein—represents a leaving group, to the OH or SH functional group of the drug HX-DM in order to obtain a compound according to formula (I) ##STR00033##
Description
EXAMPLES
Example 1
Procedure to Prepare O-Linked Drug Conjugates
(1) ##STR00016##
Route A
(2) The β-linked carbamate intermediates 3 were prepared from known 2,3,4,6-tetra-O-acetyl-D-glucopyranose 1 by reaction with appropriate isocyanates (2 eq) in toluene in the presence of triethylamine for 2-17 h at 20-60° C. until the starting material was completely converted into the carbamate. The reaction mixture was cooled to 15° C. and 3-(dimethylamino)propylamine (1.5 eq) was added. Stirring was continued for 30 min. The reaction mixture was extracted with 2M aq. HCl, water and aq. NaHCO.sub.3, dried on magnesium sulfate and evaporated to give the carbamate, which was used without further purification. In a similar fashion, 2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl, 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl and 2,3,4,6,2′,3′,6′-hepta-O-acetyl-β-D-cellobiosyl carbamates were prepared.
(3) Route B
(4) Carbamate intermediates were obtained by reaction of 1-O-(4-nitrophenoxycarbonyl)-2,3,4,6-tetra-O-acetyl-β-D-glucopyranose 2 and the appropriate amine 1.5 eq. in the presence of triethylamine (2 eq) in dichloromethane for 6-18 h. The reaction mixture was diluted with dichloromethane and extracted with water and aq. NaHCO.sub.3, dried on magnesium sulfate and concentrated. The residue was chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane to provide the pure carbamates.
(5) General Procedure for the Preparation of Drug Conjugates from Acetate Protected Glycosyl Carbamates
(6) I) Preparation of Methylene Chlorides
(7) The chloromethylene building blocks are prepared from the corresponding carbamates 3 by reaction with paraformaldehyde (1.5 eq) and trimethylsilyl chloride (3 eq) in dichloromethane until the reaction mixture becomes clear (2-18 h). Evaporation of the solvents and drying of the residue in vacuo gave the chloromethylene carbamates 4 which were used without further purification.
(8) II) Preparation of Abiraterone Conjugates 7
(9) ##STR00017##
(10) The chloromethylene derivatives 4 were reacted with either the 17-bromo- or 17-iodo-3β-hydroxy-5α-androstan-5,16-diene 6 in the presence of diisopropylethylamine in dichloromethane for 48 h. The reaction mixture was diluted with dichloromethane, extracted with brine and aq. NaHCO.sub.3, dried with magnesium sulfate and concentrated. The residues were purified by flash chromatography with an increasing gradient of ethyl acetate in heptane to give the methylene ethers.
(11) III) Deacetylation
(12) The methylene ethers were dissolved in methanol (10 mL/mM). Sodium methoxide (0.1-1 eq) was added and the reaction mixture was stirred for 1 h at room temperature. The reaction mixture was diluted with ethyl acetate and the reaction mixture was extracted with brine. The organic layer was dried (MgSO.sub.4) and evaporated. The residue was dried in vacuo.
(13) IV) Synthesis of 17-pyridyl derivatives from the 3β-substituted 17-bromo-5α-androstan-5,16-diene
(14) The 17-bromide (1 eq.), diethyl(3-pyridyl)borane (3 eq.) and triphenylphosphine (0.1 eq.) were dissolved in t-butanol and 2 M sodium carbonate in water. The mixture was degassed with nitrogen and treated with palladium tetrakis(triphenylphosphine) (0.05 eq.) for 3 h at 90° C. Water was added and the mixture was extracted with ethyl acetate. The organic layer was dried with magnesium sulfate and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to provide the abiraterone conjugates 7.
(15) V) Synthesis of 17-pyridyl derivatives from the 3β-substituted 17-iodo-5α-androstan-5,16-diene
(16) The 17-iodide (1 eq.) was dissolved in a 2:1 mixture of THF and MeOH. Diethyl(3-pyridyl)borane (3 eq) was added followed by aq. sodium carbonate (2.00 M, 3 eq). The resulting solution was degassed by bubbling N.sub.2 gas through for 30 min. After this time palladium bis(triphenylphosphine) dichloride (0.01 eq) was added and the reaction mixture was stirred at 60° C. for 2 h. Water was added and the aqueous mixture was extracted with ethyl acetate. The organic layer was dried with magnesium sulfate and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to provide the abiraterone conjugates 7.
(17) ##STR00018##
(18) 17-Iodo-3β-hydroxy-5α-androstan-5,16-diene was reacted with paraformaldehyde (1.5 eq) and trimethylsilyl chloride (3 eq) for 24 h at room temperature. The reaction mixture was concentrated to dryness. The residue was redissolved in DMF and treated with sodium azide (1.2 eq) for 1 h at room temperature. Water was added and the aqueous mixture was extracted with ethyl acetate. The organic layer was extracted with aq NaCl (×3), dried (MgSO4) and concentrated to give a brown solid which was used without further purification. The azide 8 (1 eq) and 1-O-(4-nitrophenoxycarbonyl)-2,3,4,6-tetra-O-acetyl-β-D-glucopyranose 2 (1 eq) was dissolved in dichloromethane. Triphenylphosphine (1 eq) was added and the reaction mixture was stirred for 16 h at room temperature. Triethylamine (3 eq) was added and the reaction mixture was stirred for another 24 h. The reaction mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane to give the methylene ether 9.
(19) Deacetylation and palladium-mediated coupling of the iodide with diethyl(3-pyridyl)borane was accomplished following general procedures III and V to give the unprotected abiraterone conjugate 10.
(20) ##STR00019##
(21) 1-O-(4-Nitrophenoxycarbonyl)-2,3,4,6-tetra-O-acetyl-α-D-glucopyranose [Bioorg. Med. Chem. Lett., 2016, 26, 3774] was reacted with n-propylamine (2 eq.) and triethylamine (2 eq.) in dichloromethane for 5 h. The reaction mixture was diluted with ethyl acetate, extracted with water and aq. NaHCO.sub.3. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane (0->70%) to give the α-linked n-propylcarbamate. The sequence of reactions to provide the α-linked abiraterone conjugate 11 was identical as described in the General procedure for the preparation of β-linked glucopyranosyl-drug conjugates. Starting from 1-O-p-nitrophenylcarbonyl-2,3,4,6-tetra-O-acetyl-α-D-glucopyranose the unprotected α-linked glucopyranosyl-abiraterone conjugate 11 was obtained.
(22) In a similar fashion as outlined above, unprotected β-linked galactopyranosyl-abiraterone 12 and 13, α- and β-linked mannopyranosyl-abiraterone 14a and 14b, β-linked 4-deoxy-4-fluoro-glucopyranosyl-abiraterone 15 and β-linked 6-deoxy-6-fluoro-glucopyranosyl-abiraterone 16 conjugates could be obtained starting from the corresponding glycosyl n-alkylcarbamates.
(23) The following compounds were prepared with the methods as outlined above:
(24) TABLE-US-00001
(25) UPLC-MS data were recorded on an Agilent 1200 Infinity UPLC system, attached to an Agilent 6100 single quadrupole MS detector. A Kinetex 2.6μ EVO C18 100A column of 50×2.1 mm equipped with a EVO C18 guard column (Phenomenex) was used. The UPLC experiments were run at a flow speed of 0.6 mL/min with a weakly basic solvent system consisting of 10 mM ammonium bicarbonate solution in water (A) and acetonitrile (B). When indicated, a weakly acidic solvent system consisting of 0.1% formic acid in water (A) and acetonitrile containing 0.1% formic acid (B) was used. A gradient was run from 5% B to 60% B in 1.0 minutes, followed by a gradient from 60% to 95% B in 2.0 minutes and keeping the gradient at 95% B for 1 minute.
Example 2
Procedure to Prepare O-Linked Drug Conjugates of Kalydeco
(26) ##STR00021##
(27) To a suspension of Kalydeco in dichloromethane was added propyl-chloromethyl carbamate 4 (1.1 eq) and N,N-diisopropylethylamine (2 eq). The reaction mixture was stirred for 18 h at room temperature at which time the reaction mixture had become clear. The mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane to give the methylene ether. Deacetylation was performed by dissolving the methylene ether in a 1:2 mixture of dioxane and methanol, followed by the addition of a catalytic amount of sodium methoxide. The reaction mixture was stirred for 2 h. Water was added and the resulting mixture was extracted with ethyl acetate. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected glucose-Kalydeco conjugate 17. UPLC-MS: retention time 3.06 min; Mass found 670.2 [M+H] (formic acid solvent system).
Example 3
Procedure to Prepare O-Linked Drug Conjugates of Gemcitabine
(28) ##STR00022##
(29) Gemcitabine was reacted with TBDMS-Cl (1.2 eq) in pyridine for 3 h. Water was added and the reaction mixture was concentrated. The residue was taken up in ethyl acetate and extracted with water and aq. NaHCO.sub.3, dried (MgSO.sub.4) and concentrated. The residue was dissolved in pyridine and isobutyryl chloride (2.2 eq) was added. The resulting mixture was stirred for 66 h at room temperature. Water was added and the reaction mixture was concentrated. The residue was taken up in ethyl acetate and extracted with water and aq. NaHCO.sub.3, dried (MgSO.sub.4) and concentrated and coevaporated twice with toluene. The residue was chromatographed on silica gel and eluted with an increasing gradient of methanol in dichloromethane. The pure fractions were collected and evaporated to dryness. The product obtained was dissolved in acetonitrile. 10% v/v water was added. Then, p-toluene sulfonic acid monohydrate (3 eq) was added and the reaction mixture was stirred for 66 h at room temperature. The mixture was diluted with ethyl acetate, extracted with water and aq. NaHCO.sub.3, dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the 5-OH unprotected gemcitabine derivative.
(30) This compound was reacted with the propyl-chloromethyl carbamate 4 (2 eq) in the presence of N,N-diisopropyethylamine (6 eq) for 72 h at room temperature. Water was added and the mixture was extracted with dichloromethane. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel and eluted with an increasing gradient of methanol in dichloromethane to give the methylene ether. Deacetylation was performed by dissolving the methylene ether in a 1:2 mixture of dioxane and methanol, followed by the addition of a catalytic amount of sodium methoxide. The reaction mixture was stirred for 2 h. Water was added and the resulting mixture was extracted with ethyl acetate. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected gemcitabine conjugate 20. UPLC-MS: retention time 0.327 min; Mass found 541.1 [M+H] (formic acid solvent system).
Example 4
Procedure to Prepare O-Linked Drug Conjugates of Niclosamide
(31) ##STR00023##
(32) Niclosamide 21 and propyl chloromethyl-carbamate 4 (1.3 eq) were suspended in dichloromethane. N,N-diisopropylethylamine (5 eq) was added and the reaction mixture was stirred for 16 h. The mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane. The pure fractions were concentrated and dried in vacuo. The acetylated product was dissolved in a 1:1 mixture of THF and methanol. Sodium methoxide (1 eq) was added and the reaction mixture was stirred for 1 h. Water was added and the reaction mixture was extracted with ethyl acetate. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel and eluted with an increasing gradient of methanol in dichloromethane to give the unprotected niclosamide conjugate 22. UPLC-MS: retention time 2.97 min (ES-API); Mass found (M+Na) 627.0 (formic acid solvent system).
Example 5
Procedure to Prepare O-Linked Drug Conjugates of Dihydroartemisinin
(33) ##STR00024##
(34) To a solution of dihydroartemisinin 23 and propyl chloromethyl carbamate chloride 4 (2 eq) in dichloromethane was added N,N-diisopropylethylamine (5 eq) and the mixture was stirred at RT for 48 h. The reaction mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane. The pure fractions were combined and concentrated to dryness. The obtained material was dissolved in a 1:1 mixture of THF and methanol. Sodium methoxide (1 eq) was added and the reaction mixture was stirred for 1 h. Water was added and the mixture was extracted with ethyl acetate. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected dihydroartemisinin conjugate 24. UPLC-MS: retention time 2.77 min (ES-API); [M+Na] 585.2 (formic acid solvent system).
Example 6
Procedure to Prepare 3-O-Linked Drug Conjugate 26 of Fulvestrant
(35) ##STR00025##
(36) Fulvestrant-17-O-formate was prepared from Fulvestrant 25 as reported [J. Chem. Soc., Perkin Trans. 1, 2001, 3037]. To a solution of Fulvestrant-17-O-formate (750 mg, 1.18 mmol) in methylene chloride (5 mL) was added DIPEA (1.01 mL) and the reaction mixture was stirred for 18 h. The reaction mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane. The pure fractions were combined and concentrated to dryness. The obtained material was dissolved in a 1:1 mixture of THF and methanol. Sodium methoxide (1 eq) was added and the reaction mixture was stirred for 1 h. Water was added and the mixture was extracted with ethyl acetate. The organic layer was dried (MgSO4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected Fulvestrant conjugate 26. UPLC-MS: retention time 3.23 min (ES-API) Mass found (M+Na) 907.6 (formic acid solvent system).
Example 7
Procedure to Prepare 17-O-Linked Drug Conjugate 27 of Fulvestrant
(37) 3-O-Benzoyl-Fulvestrant was prepared as reported [J. Chem. Soc., Perkin Trans. 1, 2001, 3037] and was dissolved in dichloromethane. The propyl-chloromethyl carbamate derivative 4 (1.3 eq) and DIPEA (5 eq) were added and the reaction mixture was stirred for 72 h at room temperature. The reaction mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane to give the protected Fulvestrant conjugate. The obtained product was dissolved in a 1:1 mixture of THF and methanol. Sodium methoxide (1 eq) was added and the mixture was stirred for 1 h. Water was added and the mixture was extracted with ethyl acetate. The organic layer was dried (MgSO4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected Fulvestrant conjugate 27. UPLC-MS: retention time 3.29 min (ES-API) Mass found (M+Na) 907.6 (formic acid solvent system).
Example 8
Procedure to Prepare O-Linked Drug Rotigotine Conjugate 28
(38) ##STR00026##
(39) To a solution of Rotigotine (2 mM) and propyl chloromethyl carbamate 4 (2 mM) in dichloromethane was added N,N-diisopropylethylamine (3 eq) and the mixture was stirred at RT for 24 h. The reaction mixture was concentrated and chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane. The pure fractions were combined and concentrated to dryness. The obtained material was dissolved in a 1:1 mixture of THF and methanol. Sodium methoxide (1 eq) was added and the reaction mixture was stirred for 1 h. Aqueous ammonium chloride (1 M) was added and the mixture was extracted with ethyl acetate. The organic layer was dried (MgSO.sub.4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected Rotigotine conjugate 28 (374 mg). UPLC-MS: retention time 4.46 min (ES-API); [M+H] 593.2 (formic acid solvent system).
Example 9
Procedure to Prepare O-Linked Drug Edavarone Conjugate 29
(40) ##STR00027##
(41) 5-methyl-2-phenyl-4H-pyrazol-3-one (2.54 mmol) and cesium carbonate (2.54 mmol) were stirred in acetone (10.0 mL) for 1 h. After this time chloromethyl propyl carbamate 4 in acetone (5 mL) was added. The resulting solution was stirred for 24 h. After this time the solution was filtered and concentrated. The residue was chromatographed on silica gel with an increasing gradient of ethyl acetate in heptane to give the protected Edavarone conjugate (460 mg). To a solution of the protected conjugate in MeOH (5 mL) was added sodium methoxide (68.9 mg, 1.27 mmol) and the solution stirred at RT until no starting material remained. After this time the solution was diluted with EtOAc (100 mL), washed with sodium bicarbonate solution, dried (MgSO4) and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected Edavarone conjugate 29 (274 mg). UPLC-MS: retention time 4.37 min (ES-API); [M+H] 452.2 (formic acid solvent system).
Example 10
Procedure to Prepare O-Linked Drug Conjugate 30 of Cannabidiol
(42) ##STR00028##
(43) To a solution of Cannabidiol in THF was added triethylamine (1.24 mL) followed by acetyl chloride (559 mg). The resulting solution was stirred for 2 h at RT. Water was added and the aqueous layer extracted with methylene chloride. The organic layers were dried and concentrated to give an oil which was purified by flash chromatography to give a mixture of mono- and diacetylated cannabidiol mono- and diacetate (1200 mg) which was used without further purification.
(44) To a solution of the mono- and diacetate mixture from the previous experiment (600 mg) in acetone (10.0 mL) and K.sub.2CO.sub.3 (698 mg) was added, followed by a solution of chloromethylpropyl carbamate 4 (811 mg) in acetone (10 mL). The resulting solution was stirred until no further reaction observed by LCMS. After this time the solution was filtered and concentrated. The residue was dissolved in DCM and then purified by flash chromatography to give the protected cannabidiol conjugate (480 mg).
(45) To a solution of the protected cannabidiol conjugate (480 mg) in MeOH (10 mL) was added sodium methoxide (32 mg) and the solution stirred at room temperature for 2 h. After this time saturated aq. ammonium chloride was added and the water layer was extracted with ethyl acetate, dried and concentrated. The residue was chromatographed on silica gel with an increasing gradient of methanol in dichloromethane to give the unprotected cannabidiol conjugate 30 (274 mg). UPLC-MS: retention time 3.04 min (ES-API); [M+H] 614.4 (formic acid solvent system). (328 mg).
Example 11
Determination of Oral Bioavailability of Abiraterone Conjugates
(46) Relative and absolute bioavailability may be determined in different animal models and according to different protocols. The following protocol is typical for determining bioavailability in female Beagle dogs. The animals were deprived from food over a time period of 8 h prior to administration and 2 h after administration of the test molecules. Water was supplied without limitation.
(47) On the study day, the animals received test molecules, at a single dose of 15 μmole/kg, by oral gavage, formulated in mixtures of propylene glycol, ethanol and 0.9% NaCl+5% mannitol in water. Blood samples were collected from the jugular vein on the following time points: 0.25, 0.5, 1, 2, 4, 8 and 24 hours after dosing.
(48) Circulating concentrations of test compounds were determined over a time period of 24 h using LC/MS/MS methods with demonstrated specificity and error over a concentration range of 1.0 ng/mL (LLQ) to 2500 ng/mL (1 day validation).
(49) Pharmacokinetic parameters were calculated from concentration versus time data using non-compartmental pharmacokinetic methods using Phoenix pharmacokinetic software. Data are compared to Zytiga to establish improvement of its oral bioavailability by the Abiraterone conjugates.
(50) TABLE-US-00002 Conversion rate to Compound AUC.sub.last Abiraterone 3-O-Acetate (Zytiga) o nd (comparative) 3-O-β-Glucoside (33) + + (comparative) 7a ++ +++ 7b + ++++ 7c ++ +++ 7g ++ ++ 7j ++ ++ 7k + ++++ 7l ++ +++ 7s + ++++ 13 ++ ++ AUC.sub.last (total amount abiraterone and conjugate) o AUC.sub.last value for Zytiga + 1.1-6-fold increase compared to Zytiga ++ >7-fold increase compared to Zytiga Conversion rate: AUC.sub.last Abiraterone/AUC.sub.last conjugate + AUC.sub.last Abiraterone × 100% nd = not determined + 1-20% ++ 21-40% +++ 41-50% ++++ >51%
3-O-β-D-Glucopyranosyl-abiraterone 33 was obtained according to the following scheme:
(51) ##STR00029##
(52) Known 31 was reacted with 17-bromo-3β-hydroxy-5α-androstan-5,16-diene 6 in the presence of boron trifluoride etherate to give the glucoside 32. Compound 32 was debenzoylated with sodium methoxide in methanol, followed by reaction with diethyl(3-pyridyl)borane in the presence of triphenylphosphine, palladium tetrakistriphenylphosphine and sodium carbonate to give the unprotected glucoside 33.
Example 12
Determination of Oral Bioavailability of Kalydeco Conjugates
(53) In a similar fashion as described in Example 11, the bioavailability increase of Kalydeco conjugate 17 was determined.
(54) TABLE-US-00003 Conversion rate to Compound AUC.sub.last Kalydeco Kalydeco o 17 + ++++ AUC.sub.last (total amount Kalydeco and conjugate) o AUC.sub.last value for Kalydeco + 1.1-6-fold increase compared to Kalydeco Conversion rate: AUC.sub.last Kalydeco/AUC.sub.last conjugate + AUC.sub.last Kalydeco × 100% nd = not determined + 1-20% ++ 21-40% +++ 41-50% ++++ >51%
Example 13
Determination of Oral Bioavailability of Fulvestrant Conjugates
(55) In a similar fashion as described in Example 11, the bioavailability increase of Fulvestrant conjugate 26 was determined.
(56) TABLE-US-00004 Conversion rate to Compound AUC.sub.last Fulvestrant Fulvestrant o 26 + ++++ AUC.sub.last (total amount Fulvestrant and conjugate) o AUC.sub.last value for Fulvestrant + 1.1-6-fold increase compared to Fulvestrant Conversion rate: AUC.sub.last conjugate/AUC.sub.last conjugate + AUC.sub.last Fulvestrant × 100% nd = not determined + 1-20% ++ 21-40% +++ 41-50% ++++ >51%
Example 14
Determination of Oral Bioavailability of Rotigotine Conjugate
(57) In a similar fashion as described in Example 11, the bioavailability increase of Rotigotine conjugate 28 was determined.
(58) TABLE-US-00005 Conversion rate to Compound AUC.sub.last Rotigotine Rotigotine o 28 ++ ++++ AUC.sub.last (total amount Rotigotine and conjugate) o AUC.sub.last value for Rotigotine ++ >6-fold increase compared to Rotigotine Conversion rate: AUC.sub.last conjugate/AUC.sub.last conjugate + AUC.sub.last Rotigotine × 100% nd = not determined + 1-20% ++ 21-40% +++ 41-50% ++++ >51%
(59) The above examples teach that O-glucosides of drugs, such as Abiraterone and Kalydeco did not show an increase in oral bioavailability in comparison to the parent drug. Moreover, both glucosides showed very slow hydrolysis into the parent drugs.
(60) Without wishing to be bound by any theory, it is believed that the results of the present invention are based on the use of linker moieties to improve the uptake and to achieve a more predictable hydrolysis rate of the drug glycosides. These linker moieties are positioned between the anomeric hydroxyl of the sugar residue and the drug and serve as molecular interface that create a certain distance between the sugar and drug moieties which may facilitate absorption and improve the interaction with an appropriate glycosidase. A self-immolative linker could prevent accumulation of intermediates.
(61) In a comparative experiment (results not shown) several self-immolative linkers such as diaminoethyl linker conjugates of Kalydeco and Abiraterone were prepared. Enzymatic removal of the glucose moiety of those conjugates did not result in formation of Kalydeco or Abiraterone, respectively. Rather, the intermediate aminoethyl conjugates were observed.
(62) Similar results were obtained with the glutathione-sensitive disulfanylethyl glycoconjugate of Abiraterone. Cleavage of the disulfide bond with glutathione did not produce significant amounts of Abiraterone, but rather produced the mercaptoethyl conjugate as well as various adducts. In contrast, compounds such as 7c, 7k and 17 were readily converted to Abiraterone and Kalydeco, respectively, upon treatment with β-glucosidase.
(63) These results indicate that while physicochemical characteristics of a drug can be improved by converting a drug into a drug-glycoside, significant improvement of oral bioavailability with this type of prodrug is not always achieved, contrary to the results of the invention as shown above.