CONTROLLED-RELEASE FORMULATIONS

Abstract

The present invention relates to pre-formulations comprising low viscosity, non-liquid crystalline, mixtures of: a) at least one ester of a sugar or sugar derivative; b) at least one phospholipid; c) at least one biocompatible, oxygen containing, low viscosity organic solvent; wherein the pre-formulation forms, or is capable of forming, at least one liquid crystalline phase structure upon contact with an aqueous fluid; with the proviso that the pre-formulation does not further comprise a liquid crystal hardener. The preformulations are suitable for generating parenteral, non-parenteral and topical depot compositions for sustained release of active agents. The invention additionally relates to a method of delivery of an active agent comprising administration of a preformulation of the invention, a depot composition formed by exposing pre-formulations of the invention to an aqueous fluid, a method of treatment comprising administration of a preformulation of the invention and the use of a preformulation of the invention.

Claims

1-37. (canceled)

38. A pre-formulation comprising a low viscosity, non-liquid crystalline, mixture of: i) at least one ester of a sugar or sugar derivative; ii) at least one phospholipid; iii) at least one biocompatible, oxygen containing, low viscosity organic solvent; wherein the pre-formulation forms, or is capable of forming, at least one non-lamellar liquid crystalline phase structure upon contact with an aqueous fluid; and wherein the pre-formulation does not further comprise a liquid crystal hardener.

39. A pre-formulation according to claim 38, wherein said liquid crystal hardener is any component free of an ionizable group, having a hydrophobic moiety of 15 to 40 carbon atoms with a triacyl group or a carbon ring structure.

40. A pre-formulation according to claim 38, wherein the pre-formulation does not comprise a liquid crystal hardener selected from triglycerides, retinyl palmitate, benzyl benzoate, cholesterol, ubiquinone, tocopherols or mixtures thereof.

41. A pre-formulation according to claim 38, wherein component i) comprises a mono-ester of a hexitol sugar derivative, comprising a hexitan head group and a tail group.

42. A pre-formulation according to claim 38, wherein component i) is at least one sorbitan ester.

43. A pre-formulation according to claim 38, wherein component i) comprises at least one fatty acid ester of a sorbitan comprising a sorbitan head group and one to three fatty acyl tail groups.

44. A pre-formulation as claimed in claim 43, wherein component i) comprises at least one fatty acid sorbitan di-ester comprising a sorbitan head group and two fatty acyl tail groups.

45. A pre-formulation according to claim 43, wherein each fatty acyl tail group is independently selected from caproic, caprylic, capric, lauric, myristic, palmitic, phytanic, palmitolic, stearic, iso-stearic, oleic, elaidic, linoleic, linolenic, arachidonic, behenic, or lignoceric acids.

46. A pre-formulation according to claim 38, wherein component ii) is at least one phosphatidyl choline or at least one phosphatidyl ethanolamine or mixtures thereof.

47. A pre-formulation according to claim 38, wherein component i) comprises a mixture of fatty acid mono-, di- and tri-esters of sorbitan and component ii) is phosphatidyl choline.

48. A pre-formulation according to claim 38, wherein component i) comprises at least 30% fatty acid di-esters of sorbitan.

49. A pre-formulation according to claim 38, wherein the weight ratio of i) : ii) is in the range of 30:70 to 80:20, more preferably in the range of 45:55 to 75:25.

50. A pre-formulation according to claim 49, wherein component i) comprises at least 30% fatty acid di-esters of sorbitan and component ii) is soy PC, wherein the weight ratio of i):ii) is 45:55 to 75:25, preferably 50:50 to 75:25, more preferably 55:45 to 70:30.

51. A pre-formulation according to claim 49 wherein component i) comprises at least 30% fatty acid di-esters of sorbitan and component ii) is DOPE, wherein the weight ratio of i):ii) is 25:75 to 75:25, preferably 30:70 to 75:25, more preferably 40:60 to 70:30.

52. A pre-formulation according to claim 38 having a viscosity of below 5000 mPas, preferably below 2000 mPas, preferably below 1000 mPas, more preferably below 600 mPas at 20° C.

53. A pre-formulation according to claim 38, further comprising at least one active agent.

54. A pre-formulation according to claim 53, wherein said active agent is a peptide active agent.

55. A pre-formulation as claimed in claim 53, wherein said active agent is selected from the group consisting of opioid agonists, opioid antagonists, GnRH agonists (buserelin, deslorelin, goserelin, leuprorelin/leuprolide, naferelin and triptorelin), GnRH antagonists (cetrorelix, ganirelix, abarelix, degarelix), somatostatins (SST-14 and SST-28) and somatostatin receptor (SSTR) agonists, e.g. octreotide, lanreotide, vapreotide, pasireotide, glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1(7-37), GLP-1(7-36)amide), liraglutide, exenatide, and lixisenatide (AVE0010)), and glucagon-like peptide 2 agonists (e.g. ZP1846), and mixtures thereof.

56. A pre-formulation according to claim 53, wherein the active agent is an opioid agonist selected from the group consisting of buprenorphine, fentanyl, sufentanil, remifentanil, oxymorphone, dimorphone, dihydroetorphine, and diacetylmorphine; or wherein the active agent is an opioid antagonist selected from the group consisting of naloxone, nalmefene, and naltrexone.

57. A pre-formulation according to claim 53, wherein said active agent is a cyclic peptide of 30 or fewer amino acids, preferably 15 or fewer.

58. A pre-formulation according to claim 53, wherein said active agent is a somatostatin analogue.

59. A pre-formulation according to claim 38, wherein the pre-formulation does not contain any non-peptide bioactive agents.

60. A pharmaceutical formulation comprising the pre-formulation of claim 38.

61. The pharmaceutical formulation of claim 60 additionally comprising at least one pharmaceutically tolerable carrier or excipient.

62. A depot composition formed by exposing a pre-formulation as claimed in claim 38 to an aqueous fluid in vivo.

63. A method of delivery of a bioactive agent to a human or non-human animal (preferably mammalian) body, this method comprising administering a pre-formulation comprising a non-liquid crystalline, low viscosity mixture of: i) at least one ester of a sugar or sugar derivative; ii) at least one phospholipid; iii) at least one biocompatible, oxygen containing, low viscosity organic solvent; and wherein at least one bioactive agent is dissolved or dispersed in the low viscosity mixture, whereby to form at least one non-lamellar liquid crystalline phase structure upon contact with an aqueous fluid in vivo following administration, wherein the pre-formulation does not further comprise a liquid crystal hardener.

64. The method according to claim 63, wherein component i) comprises a sorbitan ester, preferably a mixture comprising fatty acid mono-, di- and tri-esters of sorbitan.

65. A method for the preparation of a liquid crystalline composition comprising exposing a pre-formulation as claimed in claim 38 to an aqueous fluid in vivo.

66. A process for the formation of a pre-formulation according to claim 38 suitable for the administration of a bioactive agent to a (preferably mammalian) subject, said process comprising forming a non-liquid crystalline, low viscosity mixture of i) at least one ester of a sugar or sugar derivative; ii) at least one phospholipid; iii) at least one biocompatible, oxygen containing, low viscosity organic solvent; and dissolving or dispersing at least one bioactive agent in the low viscosity mixture, or in at least one of components i), ii) or iii) prior to forming the low viscosity mixture.

67. The process of claim 66, wherein component i) comprises a sorbitan ester, preferably a mixture comprising fatty acid mono-, di- and tri-esters of sorbitan.

68. A method of treatment or prophylaxis of a human or non-human animal subject comprising administering of a pre-formulation as claimed in claim 38.

69. A pre-filled administration device containing a pre-formulation as claimed in claim 38.

70. The device as claimed in claim 69, wherein the device is a syringe or syringe barrel, a needle-less injector, a multi- or single-use injector, a cartridge or a vial.

71. The device of claim 69 equipped with an injection aid, such as an auto-injector.

72. A kit comprising an administration device as claimed in claim 69.

73. A method of delivery of a pre-formulation to a subject in need thereof, the method involving administering a pre-formulation as claimed in claim 38 using a pre-filled administration device.

Description

FIGURES

[0173] FIG. 1 illustrates formulation viscosity against the proportion of phospholipid in respect to total lipid content.

[0174] FIG. 2 shows synchrotron small-angle X-ray diffraction (SAXD) measurements illustrating the liquid crystalline structure of the SPC/Span® 80 mixtures.

[0175] FIG. 3 shows synchrotron small-angle X-ray diffraction (SAXD) measurements illustrating the liquid crystalline structure of the DOPC/Span® 80 mixtures.

[0176] FIG. 4 shows synchrotron small-angle X-ray diffraction (SAXD) measurements illustrating the liquid crystalline structure of the DOPE/Span® 80 mixtures.

[0177] FIG. 5 shows X-ray diffraction patterns of fully hydrated SPC/Span® 80/VitEAc mixtures.

[0178] FIG. 6 shows the in vitro release of leuprolide acetate from SPC/Span® 80 and comparative SPC/Span®80/VitEAc and SPC/GDO formulations containing 2.1 wt % of LEU.

[0179] FIG. 7 shows the in vitro release of octreotide from SPC/Span® 80 and comparative SPC/Span® 80/VitEAc and SPC/GDO formulations containing 2.3 wt % of OCT.

EXAMPLES

[0180] Materials

[0181] Soy phosphatidylcholine (SPC)—Lipoid S100 from Lipoid, Germany

[0182] Dioleoylphosphatidylcholine (DOPC)—from NOF, Japan

[0183] Dioleoylphosphatidylethanolamine (DOPE)—Lipoid PE 18:1/18:1 from Lipoid, Germany

[0184] Sorbitan monooleate (Span® 80)—from Sigma-Aldrich, Sweden

[0185] Vitamin E acetate (VitEAc)—from Sigma-Aldrich, Sweden

[0186] Glycerol dioleate (GDO)—Cithrol GDO from Croda, UK

[0187] Ethanol (EtOH) 99.5% Ph. Eur.—from Solveco, Sweden

[0188] Leuprolide acetate (LEU)—from PolyPeptide Labs., USA

[0189] Octreotide hydrochloride (OCT)—from PolyPeptide Labs., USA

[0190] Phosphate buffered saline (PBS) tablets—from Sigma-Aldrich, Sweden

[0191] Water for Injection (WFI)—from B. Braun, Germany

[0192] All other chemicals were of analytical grade purity

Example 1

Liquid Formulations Comprising Soy Phosphatidylcholine And Span® 80

[0193] Precursor formulations containing different proportions of soy phosphatidylcholine (SPC), sorbitan monooleate (Span® 80) and ethanol (EtOH) as solvent were prepared. Appropriate amounts of SPC, Span® 80 and EtOH (3 g in total) were weighed in 6R injection glass vials. Sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). Sample compositions are given in Table 2.

TABLE-US-00002 TABLE 2 Compositions of SPC/Span ®80/EtOH formulations. Formulation SPC Span ®80 EtOH SPC/Span ®80 No (wt %) (wt %) (wt %) (weight ratio) #1 63.00 27.00 10.00 70/30 #2 54.00 36.00 10.00 60/40 #3 49.50 40.50 10.00 55/45 #4 45.00 45.00 10.00 50/50 #5 40.50 49.50 10.00 45/55 #6 36.00 54.00 10.00 40/60 #7 31.50 58.50 10.00 35/65 #8 27.00 63.00 10.00 30/70 #9 22.50 67.50 10.00 25/75 #10 18.00 72.00 10.00 20/80 #11 13.50 76.50 10.00 15/85 #12 9.00 81.00 10.00 10/90

Example 2

Liquid Formulations Comprising Dioleoylphosphatidylcholine and Span® 80

[0194] Precursor formulations containing different proportions of dioleoylphosphatidylcholine (DOPC), sorbitan monooleate (Span® 80) and ethanol (EtOH) as solvent were prepared. Appropriate amounts of DOPC, Span® 80 and EtOH (3 g in total) were weighed in 6R injection glass vials. Sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). Sample compositions are given in Table 3.

TABLE-US-00003 TABLE 3 Compositions of DOPC/Span ®80/EtOH formulations. Formulation DOPC Span ®80 EtOH DOPC/Span ®80 No (wt %) (wt %) (wt %) (weight ratio) #13 54.00 36.00 10.00 60/40 #14 45.00 45.00 10.00 50/50 #15 36.00 54.00 10.00 40/60

Example 3

Liquid Formulations Comprising Dioleoylphosphatidylethanolamine and Span® 80

[0195] Precursor formulations containing different proportions of dioleoylphosphatidylethanolamine (DOPE), sorbitan monooleate (Span® 80) and ethanol (EtOH) as solvent were prepared. Appropriate amounts of DOPE, Span® 80 and EtOH (3 g in total) were weighed in 6R injection glass vials. Sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). Sample compositions are given in Table 4.

TABLE-US-00004 TABLE 4 Compositions of DOPE/Span ®80/EtOH formulations. Formulation DOPE Span ®80 EtOH DOPE/Span ®80 No (wt %) (wt %) (wt %) (weight ratio) #16 54.00 36.00 10.00 60/40 #17 45.00 45.00 10.00 50/50 #18 36.00 54.00 10.00 40/60

Example 4

Liquid Formulations Comprising Soy Phosphatidylcholine, Vitamin E Acetate and Span® 80

[0196] For comparison, formulations containing different proportions of soy phosphatidylcholine (SPC), sorbitan monooleate (Span® 80), ethanol (EtOH) as solvent and vitamin E acetate (VitEAc) as liquid crystalline “hardener” were prepared. Appropriate amounts of SPC, Span® 80, EtOH and VitEAc (3 g in total) were weighed in 6R injection glass vials. Sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). Sample compositions are given in Table 5.

TABLE-US-00005 TABLE 5 Compositions of SPC/Span ®80/VitEAc/EtOH formulations. SPC/(Span ®80 + Formulation SPC Span ®80 VitEAc EtOH VitEAc) No (wt %) (wt %) (wt %) (wt %) (weight ratio) #19 63.00 18.00 9.00 10.00 70/30 #20 54.00 27.00 9.00 10.00 60/40 #21 45.00 36.00 9.00 10.00 50/50 #22 36.00 45.00 9.00 10.00 40/60 #23 27.00 54.00 9.00 10.00 30/70

Example 5

Liquid Formulations Comprising Soy Phosphatidylcholine and Glycerol Dioleate

[0197] For comparison, formulations containing different proportions of soy phosphatidylcholine (SPC), glycerol dioleate (GDO) and ethanol (EtOH) as solvent were prepared. Appropriate amounts of SPC, GDO and EtOH (3 g in total) were weighed in 6R injection glass vials. Sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). Sample compositions are given in Table 6.

TABLE-US-00006 TABLE 6 Compositions of SPC/GDO/EtOH formulations. Formulation SPC GDO EtOH SPC/GDO No (wt %) (wt %) (wt %) (weight ratio) #24 63.00 27.00 10.00 70/30 #25 54.00 36.00 10.00 60/40 #26 49.50 40.50 10.00 55/45 #27 45.00 45.00 10.00 50/50 #28 40.50 49.50 10.00 45/55 #29 36.00 54.00 10.00 40/60 #30 31.50 58.50 10.00 35/65 #31 27.00 63.00 10.00 30/70

Example 6

Viscosity of Liquid Formulations Comprising Phospholipid and Span ® 80

[0198] Viscosity measurements were performed on formulations prepared in Examples 1-5. Measurements were performed using CAP 2000+ high torque viscometer (Brookfield, Mass.) equipped with CAP01 cone spindle at a share rate of 4000 s.sup.−1 (rotation speed 300 rpm) at 25° C. 75 μl of the formulation was placed between holding plate and cone spindle, equilibrated for 10 s and measured for 15 s.

[0199] FIG. 1 illustrates formulation viscosity against the proportion of phospholipid in respect to total lipid content. The general trend is that lower PC content in respect to total lipid results in a lower viscosity formulation. Formulations of the Invention illustrated in FIG. 1 include SPC/Span® 80/EtOH, DOPC/Span® 80/EtOH and DOPE/Span® 80/EtOH. The viscosity of these Formulations can be as low as the comparative SPC/GDO/EtOH system, although a significantly lower PC content is required in the PC/Span® 80 system to achieve the same viscosity as in the PC/GDO system. The viscosity of the phospholipid/Span/EtOH system is practically not affected by the additional presence of VitEAc.

Example 7

Liquid Crystalline Phase Structures From Phospholipid/Span® 80 Mixtures in the Presence of Aqueous Phase

[0200] 200 mg of each of the formulation from Examples 1-5 was injected into 5 mL PBS solution in injection 10R glass vials using disposable 1 mL Luer-Lock syringes and 21G needles. Prepared samples were left to equilibrate for 1 week before further analysis.

[0201] The nanostructure of equilibrated liquid crystalline phases was studied using synchrotron small-angle X-ray diffraction (SAXD) measurements, which were performed at the I911-4beamline at MAX-lab (Lund University, Sweden), using a 1M PILATUS 2D detector containing a total of 981×1043 pixels. Samples were mounted between kapton windows in a steel sample holder at the sample to detector distance of 1917 mm. Diffractograms were recorded with a wavelength of 0.91 Å and the beam size of 0.25×0.25 mm (full width at the half-maximum) at the sample. Silver behenate calibrated sample-to-detector distance and detector positions were used. Temperature control within 0.1° C. was achieved using computer controlled Julabo heating circulator F12-MC (Julabo Labortechnik GMBH, Seelbach, Germany). The experiments were performed successively at 25, 37, and 42° C. with a 60 s exposure time at each temperature and a wait of 10 minutes between temperature steps. The resulting CCD images were integrated and analyzed using the Fit2D software.

[0202] The obtained results for various lipid mixtures are summarized in FIGS. 2-5. The relative diffraction peak positions in FIG. 2 indicate that the liquid crystalline structure of the SPC/Span® 80 mixtures changes from reversed bicontinuous cubic (V.sub.2) at low Span® 80 content to reversed hexagonal (H.sub.2) and then to reversed micellar phase (L.sub.2) when the Span® 80 content is increased. FIG. 3 shows that the liquid crystalline structure of the DOPC/Span® 80 changes from a mixture of reversed bicontinuous cubic (V.sub.2) and reversed hexagonal (H.sub.2) phase at DOPC/Span® 80 weight ratios of 60/40 and 50/50 to pure H.sub.2 phase at DOPC/Span® 80 weight ratio of 40/60. The relative diffraction peak positions in FIG. 4 indicate that the liquid crystalline structure of the DOPE/Span® 80 changes from a mixture of reversed micellar cubic (I.sub.2, space group Fd3m) and reversed hexagonal (H.sub.2) phase at DOPE/Span®80 weight ratio of 60/40 to pure reversed micellar cubic (I.sub.2, space group Fd3m) at DOPE/Span® 80 weight ratios of 50/50 and 40/60.

[0203] For comparison, FIG. 5 shows X-ray diffraction patterns of fully hydrated SPC/Span® 80/VitEAc mixtures between weight ratios of 70/20/10 and 30/60/10 as indicated in the figure. The relative diffraction peak positions indicate that the liquid crystalline structure changes from reversed mixtures of bicontinuous cubic (V.sub.2) and intermediate phase at low Span® 80 content to reversed reversed hexagonal (H.sub.2) and then to reversed micellar phase (L.sub.2) when the Span® 80 content is increased.

[0204] Overall, data presented in FIGS. 2-4 show a general trend of the non-lamellar phase formation in lipid mixtures comprising phospholipid and Span® 80: At high phospholipid content, bicontinuous structures are formed which with increasing Span® 80 proportion in the mixture first are transformed into reversed hexagonal (or reversed micellar cubic phase in the case of DOPE) and then into reversed micellar phase. When comparing with FIG. 5, the data also show that the presence of 10 wt % (of total lipid content) of liquid crystal “hardener” (VitEAc) does not influence the type of the non-lamellar liquid crystalline structures or the observed phase transformation sequence observed without the VitEAc.

Example 8

In Vitro Release of Leuprolide Acetate from Phospholipid/Span® 80 Mixtures in the Presence of Aqueous Phase

[0205] To 0.95 g of each of the formulations #4, #6, #21, #22, #27 and #29 was added 29 mg of DMSO and 21 mg of leuprolide acetate (LEU) to get 2.1 wt % (or 2.0 wt % when corrected for peptide content and purity) of LEU in total. Assignment of the prepared samples (L1-L6) is given in Table 7.

TABLE-US-00007 TABLE 7 Compositions of LEU containing formulations for in vitro release experiments. Sample Formulation LEU DMSO Lipid weight ratio No (g) (g) (g) (wt %) L1 0.95 0.021 0.029 SPC/Span ®80 = 50/50 L2 0.95 0.021 0.029 SPC/Span ®80 = 40/60 L3 0.95 0.021 0.029 SPC/Span ®80/VitEAc = 50/40/10 L4 0.95 0.021 0.029 SPC/Span ®80/VitEAc = 40/50/10 L5 0.95 0.021 0.029 SPC/GDO = 50/50 L6 0.95 0.021 0.029 SPC/GDO = 40/60

[0206] 5 mL PBS solution was added into injection vials (6R), followed by slow addition (with the help of a 1 mL single-use Luer Lock syringe equipped with an 18G needle) of approximately 100 mg/vial of each sample (L1-L6) containing LEU (3 replicates/formulation). The vials were sealed and placed on a shaking table (150 rpm) at 37° C. Sampling from each vial (200 μl/sample) was carried out after 24 h, 48 h and 14 days of incubation, and the aliquots were transferred into polypropylene HPLC micro vials.

[0207] Determination of LEU in the samples from in vitro release experiments was carried out by HPLC-UV, against calibration standards of the LEU in PBS, prepared in the concentration range 0.2-100 μg/mL (covering approximately the release range 0.05-25% of the maximal theoretical amount of peptide to be released). The HPLC-UV conditions were: Analytical column: ACE Excel 2 C18, 20×2.1 mm; column temperature: 50° C.; Mobile phase A (MP A): 0.1% trifluoroacetic acid (TFA) in water; Mobile phase B (MP B): 0.1% TFA in acetonitrile:methanol:water (90:5:5 v/v); Flow rate: 0.6 mL/min; Gradient: t0.0: 10% MP B; t0.2: 10% MP B; t4.2: 100% MP B; t4.7: 100% MP B; t5.0: 10% MP B; t6.5: 10% MP B; Injection volume: 10 μL; Detection wavelength: 220 nm.

[0208] FIG. 6 illustrates the in vitro release of LEU from SPC/Span® 80 and comparative SPC/Span® 80/VitEAc and SPC/GDO formulations containing 2.1 wt % of LEU. The data clearly show a dramatic reduction in the burst release seen after 1 and 2 days when moving from a SPC/Span® 80 weight ratio of 50/50 (L1) to ratio of 40/60 (L2) which may be related to the different non-lamellar nanostructure (H.sub.2 phase) in the latter case. After 14 days, a clear difference in released amount of LEU between the formulations is still observed. Importantly, the addition of the liquid crystal “hardener” VitEAc (samples L3 and L4) did not slow down the release of LEU. After 14 days the released amount of LEU from samples L3 and L4 was practically the same as in the case of SPC/Span® 80 formulation prepared at lipid weight ratio of 40/60 (L2). The comparative SPC/GDO formulations (L5, L6) showed the slowest in vitro LEU release, both initially and up to 14 days.

Example 9

In Vitro Release of Octreotide Hydrochloride from Phospholipid/Span® 80 Mixtures in the Presence of Aqueous Phase

[0209] To 0.977 g of each of the formulations #4, #6, #21, #22, #27 and #29 was added 23 mg of octreotide hydrochloride (OCT) to get 2.3 wt % (or 2.0 wt % when corrected for peptide content and purity) of OCT in total. Assignment of the prepared samples (O1-O6) is given in Table 8.

TABLE-US-00008 TABLE 8 Compositions of OCT containing formulations for in vitro release experiments. Sample Formulation OCT Lipid weight ratio No (g) (g) (wt %) O1 0.977 0.023 SPC/Span ®80 = 50/50 O2 0.977 0.023 SPC/Span ®80 = 40/60 O3 0.977 0.023 SPC/Span ®80/VitEAc = 50/40/10 O4 0.977 0.023 SPC/Span ®80/VitEAc = 40/50/10 O5 0.977 0.023 SPC/GDO = 50/50 O6 0.977 0.023 SPC/GDO = 40/60

[0210] In vitro release experiments were further carried out as in Example 8 (the same HPLC assay but with calibration standards of OCT in PBS).

[0211] FIG. 7 illustrates the in vitro release of OCT from SPC/Span® 80 and comparative SPC/Span® 80/VitEAc and. SPC/GDO formulations containing 2.3 wt % of OCT. Overall, the obtained data are very similar to that given in Example 8. Here also a dramatic reduction in the burst release seen after 1 and 2 days when moving from a SPC/Span® 80 ratio of 50/50 (O1) to ratio of 40/60 (O2) is observed which may be related to the different non-lamellar nanostructure (H.sub.2 phase) in the latter case. After 14 days, a clear difference in released amount of OCT between the formulations is still observed. Importantly, the addition of the liquid crystal “hardener” VitEAc (samples O3 and O4) did not markedly change the release profile of OCT. After 14 days the released amount of OCT from samples O3 and O4 was practically the same or higher compared with the SPC/Span® 80 formulation prepared at lipid weight ratio of 40/60 (O2). The comparative SPC/GDO formulations (O5, O6) showed the slowest in vitro OCT release, both initially and up to 14 days.