WO2018211413A1

WO2018211413A1 - Solid forms of obeticholic acid and process for preparation

Info

Publication number: WO2018211413A1
Application number: PCT/IB2018/053377
Authority: WO
Inventors: Deepika PATHIVADA; Vamsi Krishna Mudapaka; Anish Gupta
Original assignee: Dr. Reddy’S Laboratories Limited
Priority date: 2017-05-15
Filing date: 2018-05-15
Publication date: 2018-11-22

Abstract

The invention of the present application relates to crystalline forms of obeticholic acid and process for preparation thereof. Specifically, the invention of present application relates to crystalline forms VD1, VD2, VD3, VD4 and VD5 of obeticholic acid. Specifically, crystalline form VD2 is stable and has excellent physic-chemical properties. Crystalline form VD2 is may be easily formulated into a pharmaceutical composition comprising obeticholic acid.

Description

SOLID FORMS OF OBETICHOLIC ACID AND PROCESS FOR PREPARATION

THEREOF

FIELD OF INVENTION

The present application relates to crystalline forms of obeticholic acid and process for preparation thereof. Specifically, the present application relates to crystalline forms VDl, VD2, VD3, VD4 and VD5 of obeticholic acid and process for preparation thereof.

BACKGROUND OF INVENTION

The PCT patent application, WO2013192097A1 (hereinafter referred as the WO'097 application) discloses crystalline form C of obeticholic acid. WO'097 application also discloses a process for preparing pure amorphous form of obeticholic acid comprising the step of converting crystalline form C of obeticholic acid to pure amorphous form. Amorphous form has been designated as form 1 in the WO'097 application. Its family equivalent, US20160108082A1 (hereinafter referred as the US' 082 application) discloses crystalline forms A, D, F, G and I of obeticholic acid. It has been reported that none of these crystalline forms are suitable for use in pharmaceutical formulation comprising obeticholic acid. Another PCT patent application, WO2016107575A1 (hereinafter referred as the WO' 575 application) discloses crystalline form A of obeticholic acid. Yet another PCT patent application, WO2017008773 A 1 (hereinafter referred as the WO '773 application) discloses crystalline forms 1-2 and 1-3 of obeticholic acid. Still another PCT application WO2017115324A1 (hereinafter referred as the WO'324 application) discloses crystalline forms α, β, γ and δ of obeticholic acid.

In general, polymorphism refers to the ability of a substance to exist as two or more crystalline phases that have different spatial arrangements and/or conformations of molecules in their crystal lattices. Thus, "polymorphs" refer to different crystalline forms of the same pure substance in which the molecules have different spatial arrangements of the molecules, atoms, and/or ions forming the crystal. Different polymorphs may have different physical properties such as melting points, solubilities, etc. The variation in solid forms may appreciably influence the pharmaceutical properties, such as bioavailability, handling properties, dissolution rate, and stability, and in turn such properties can significantly influence the processing, shelf life, and commercial acceptance of a polymorphic form. For these reasons, regulatory authorities require drug manufacturing companies to put efforts into identifying all polymorphic forms, e.g., crystalline, amorphous, solvates, stable dispersions with a pharmaceutically acceptable carriers, etc., of new drug substances.

The existence and possible numbers of polymorphic forms for a given compound cannot be predicted, and there are no "standard" procedures that can be used to prepare polymorphic forms of a substance. This is well-known in the art, as reported, for example, by A. Goho, "Tricky Business," Science News, Vol. 166(8), August 2004.

Hence, there remains a need for alternate polymorphic forms of Obeticholic acid, which are stable and can be utilized for preparation of pharmaceutical formulation comprising obeticholic acid.

SUMMARY OF INVENTION

First aspect of the present application relates to crystalline form VD1 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.15, 4.16, 6.29, 9.00, 11.03 and 15.43 ± 0.2° 2Θ. In embodiments, the present application provides crystalline form VD 1 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 9.43, 9.89, 12.43 and 16.75 ± 0.2° 2Θ.

Second aspect of the present application relates to crystalline form VD1 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 1.

Third aspect of the present application relates to a process for preparing crystalline form VD 1 of obeticholic acid comprising

a) dissolving obeticholic acid in a solvent comprising ethyl formate;

b) optionally filtering the un-dissolved particles;

c) isolating crystalline form of obeticholic acid from the solution of step b); and

d) optionally, drying the isolated product at a suitable temperature.

Fourth aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD 1 of Obeticholic acid and one or more pharmaceutically acceptable excipient.

Fifth aspect of the present application relates to crystalline form VD2 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.19, 6.37, 10.74, 16.00, 18.15 and 18.80 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD2 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 7.75 and 9.30 ± 0.2° 2Θ. Sixth aspect of the present application relates to crystalline form VD2 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 2.

Seventh aspect of the present application relates to crystalline form VD2 of obeticholic acid characterized by a DSC thermogram substantially as illustrated in Figure 3.

Eighth aspect of the present application relates to a process for preparing crystalline form VD2 of Obeticholic acid comprising drying crystalline form VD1 of obeticholic acid at a suitable temperature.

Ninth aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD2 of obeticholic acid and one or more pharmaceutically acceptable excipient.

Tenth aspect of the present application relates to crystalline form VD3 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 4.14, 8.97, 10.81 and 15.91 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD3 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 4.70, 7.82, 8.25 and 9.37 ± 0.2° 2Θ.

Eleventh aspect of the present application relates to crystalline form VD3 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 4 & Figure 5.

Twelfth aspect of the present application relates to crystalline form VD3 of obeticholic acid characterized by DSC thermogram substantially as illustrated in Figure 6.

Thirteenth aspect of the present application relates to a process for preparing crystalline form VD3 of obeticholic acid comprising

a) mixing obeticholic acid in a solvent comprising toluene;

b) optionally filtering the un-dissolved particles;

c) isolating crystalline form VD3 of obeticholic acid from the solution of step b); and

d) optionally, drying the isolated product at a suitable temperature.

Fourteenth aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD3 of obeticholic acid and one or more pharmaceutically acceptable excipient.

Fifteenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.19, 6.37, 10.68, 15.98 and 18.75 ± 0.2° 2Θ. In embodiments, the present application provides crystalline form VD4 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 8.19 and 9.30 ± 0.2° 2Θ. Sixteenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 7.

Seventeenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized DSC thermogram substantially as illustrated in Figure 8.

Eighteenth aspect of the present application relates to a process for preparing crystalline form VD4 of obeticholic acid comprising drying crystalline form VD3 of obeticholic acid at a suitable temperature.

Nineteenth aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD4 of obeticholic acid and one or more pharmaceutically acceptable excipient.

Twentieth aspect of the present application relates to crystalline form VD5 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 6.31, 8.88, 10.36, 14.37, 14.92, 15.81 and 16.58 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD5 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 4.35, 5.14, 7.53, 9.44, 10.00, 12.25 and 12.68 ± 0.2° 2Θ.

Twenty first aspect of the present application provides crystalline form VD5 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 9.

Twenty second aspect of the present application relates to a process for preparing crystalline form VD5 of obeticholic acid comprising

a) mixing obeticholic acid in a solvent comprising cyclohexane;

b) optionally filtering the un-dissolved particles;

c) isolating crystalline form VD5 of obeticholic acid from the solution of step b); and

d) optionally, drying the isolated product at suitable a temperature.

Twenty third aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD5 of obeticholic acid and one or more pharmaceutically acceptable excipient.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 is an illustration of a PXRD pattern of crystalline form VD 1 of Obeticholic acid.

Figure 2 is an illustration of a PXRD pattern of crystalline form VD2 of Obeticholic acid.

Figure 3 is an illustration of DSC thermogram of crystalline form VD2 of Obeticholic acid.

Figure 4 is an illustration of a PXRD pattern of crystalline form VD3 of Obeticholic acid. Figure 5 is an illustration of a PXRD pattern of crystalline form VD3 of Obeticholic acid.

Figure 6 is an illustration of overlay of DSC and TGA thermograms of crystalline form VD3 of

Obeticholic acid.

Figure 7 is an illustration of a PXRD pattern of crystalline form VD4 of Obeticholic acid.

Figure 8 is an illustration of overlay of DSC and TGA thermograms of crystalline form VD4 of

Obeticholic acid.

Figure 9 is an illustration of a PXRD pattern of crystalline form VD5 of Obeticholic acid.

DETAILED DESCRIPTION OF INVENTION

First aspect of the present application relates to crystalline form VD1 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.15, 4.16, 6.29, 9.00, 11.03 and 15.43 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD 1 of Obeticholic acid characterized by its PXRD pattern having additional peaks located at about 9.43, 9.89, 12.43 and 16.75 ± 0.2° 2Θ.

Second aspect of the present application provides crystalline form VD1 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 1.

Third aspect of the present application provides a process for preparing crystalline form VD1 of obeticholic acid comprising

a) dissolving obeticholic acid in a solvent comprising ethyl formate;

b) optionally filtering the un-dissolved particles;

d) optionally, drying the isolated product at suitable temperature.

In embodiments of step a), the solvent may be a mixture of ethyl formate and an organic solvent. The organic solvent may include but not limited to, alcohols such as methanol, isopropanol and the like; ketones such as acetone, methyl isobutyl ketone and the like; ethers such as diethyl ether, tetrahydrofuran and the like; esters such as ethyl acetate, propyl acetate and the like. In another embodiment of step a), the solvent may be a mixture of ethyl formate and water. In a specific embodiment, the solvent may be ethyl formate. In one embodiment of step a), a mixture of obeticholic acid and a solvent comprising ethyl formate may be heated to dissolve obeticholic acid in the solvent. In a specific embodiment, a mixture of obeticholic acid and a solvent comprising ethyl formate may be heated at about 35 °C to about 45 °C to dissolve obeticholic acid in the solvent.

In one of the embodiments of step a), any physical form of obeticholic acid may be utilized, which may be crystalline or amorphous, for providing the solution of obeticholic acid in a solvent comprising ethyl formate. In another embodiment of step a), any physical form of obeticholic acid may be utilized, which may be anhydrous or hydrate, for providing the solution of obeticholic acid in a solvent comprising ethyl formate. In yet another embodiment, amorphous form of obeticholic acid, as reported in the WO'097 application may be used in step a). In still another embodiment, crystalline forms A, D, F, G and I of obeticholic acid, as reported in the US'082 application may be used in step a).

In one embodiment, the crystalline form VD 1 of obeticholic acid may optionally be added to the solution of obeticholic acid in a solvent comprising ethyl formate as seed crystals.

Isolation of crystalline form VDl of obeticholic acid in step c) may be performed by any technique known in the art. In one embodiment, isolation crystalline form VDl of obeticholic acid in step c) may involve methods including crystallization, evaporation, concentrating the mass, adding an anti-solvent, adding seed crystals to induce crystallization, or the like. Preferably isolation crystalline form VD 1 of obeticholic acid in step c) may be carried out by slow solvent evaporation or crystallization followed by filtration. Optionally, the crystalline form VDl may be dried under suitable condition. Drying may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 60 °C and more specifically less than about 40 °C and most specifically at 25 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer.

The crystalline form VDl of obeticholic acid may optionally be subjected to a particle size reduction procedure to produce desired particle sizes and distributions. Milling or micronization may be performed before drying, or after the completion of drying of crystalline form VDl of obeticholic acid. Equipment that may be used for particle size reduction includes but not limited to ball mill, roller mill, hammer mill, and jet mill. The crystalline form VDl of obeticholic acid of the present application is stable and has excellent physico-chemical properties. The crystalline form VDl of obeticholic acid of the present application may be easily formulated into a pharmaceutical composition comprising Obeticholic acid.

Fifth aspect of the present application relates to crystalline form VD2 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.19, 6.37, 10.74, 16.00, 18.15 and 18.80 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD2 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 7.75 and 9.30 ± 0.2° 2Θ.

Sixth aspect of the present application relates to crystalline form VD2 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 2.

Eighth aspect of the present application relates to a process for preparing crystalline form VD2 of obeticholic acid comprising drying crystalline form VDl of obeticholic acid at a suitable temperature.

In one embodiment of the present application, drying of crystalline form VDl of obeticholic acid may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 120 °C and more specifically less than about 100 °C and most specifically at 80 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer. Another embodiment of the present application relates to a process for preparation of crystalline formVD2 of Obetichohc acid comprising,

a) dissolving obeticholic acid in ethyl formate;

b) cooling the reaction mass of step a);

c) isolating the solid from step b); and

d) drying the solid of step c).

In embodiments of step a), a mixture of obeticholic acid and ethyl formate may be heated to room temperature or elevated temperature. In another embodiment, the mixture of obeticholic acid and ethyl formate may be heated to about 35-60 °C. In a specific embodiment, the mixture of obeticholic acid and ethyl formate may be heated to about 40-50 °C.

In embodiments of step a), any physical form of obeticholic acid may be utilized, which may be crystalline or amorphous, for providing the solution of obeticholic acid in a solvent comprising toluene. In another embodiment of step a), any physical form of obeticholic acid may be utilized, which may be anhydrous or hydrate, for providing the solution of obeticholic acid in a solvent comprising toluene. In yet another embodiment, amorphous form of obeticholic acid and crystalline form C of Obeticholic acid as reported in the WO '097 application may be used in step a). In still another embodiment, crystalline forms A, D, F, G and I of obeticholic acid, as reported in the US' 082 application may be used in step a).

In embodiments of step b), the reaction mass may be cooled to about 20-30 °C. In a specific embodiments of step b), the reaction mass may be further cooled to about 0-8 °C. More specifically, the reaction mass may be cooled to at about 4 °C.

In embodiments of step c) the solid as obtained in step b) may be isolated by any technique known in the art. Specifically, the solid may be isolated from the mixture of step b) by filtration.

In embodiments of step d), the solid of step c) may be dried under suitable condition. Drying may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 150 °C and more specifically less than about 120 °C and most specifically at 80 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer. The crystalline form VD2 of obeticholic acid may optionally be subjected to a particle size reduction procedure to produce desired particle sizes and distributions. Milling or micronization may be performed before drying, or after the completion of drying of crystalline form VD2 of obeticholic acid. Equipment that may be used for particle size reduction includes but not limited to ball mill, roller mill, hammer mill, and jet mill.

In one embodiment of the present application, crystalline formVD2 of Obeticholic acid may be anhydrous.

The crystalline form VD2 of obeticholic acid of the present application is stable and has excellent physico-chemical properties. The crystalline form VD2 of obeticholic acid of the present application may be easily formulated into a pharmaceutical composition comprising obeticholic acid.

In one embodiment, crystalline form VD2 of obeticholic acid is found to be stable for 3 months in any conditions namely, at 40 °C/ 75% RH; at 25 °C/ 60% RH; and at 2-8 °C.

Eleventh aspect of the present application relates to crystalline form VD3 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 4 or Figure 5.

In one embodiment of the present application relates to crystalline form VD3 of obeticholic acid characterized by TGA thermogram substantially as illustrated in Figure 6. Crystalline form VD3 of obeticholic acid may be toluene solvate. Toluene may be present in crystalline form VD3 of obeticholic acid in a range of about 3.0 to 4.0 % w/w. Specifically, toluene may be present in crystalline form VD3 of obeticholic acid is about 3.5 % w/w.

a) mixing obeticholic acid in a solvent comprising toluene;

b) optionally filtering the un-dissolved particles;

d) optionally, drying the isolated product at suitable temperature.

In embodiments of step a), the solvent may be a mixture of toluene and an organic solvent. The organic solvent may include but not limited to, alcohols such as methanol, isopropanol and the like; ketones such as acetone, methyl isobutyl ketone and the like; hydrocarbon solvents such as cyclohexane, cycloheptane and the like; ethers such as diethyl ether, tetrahydrofuran and the like; esters such as ethyl acetate, propyl acetate and the like. In a specific embodiment, the solvent may be toluene.

In one embodiment of step a), a mixture of obeticholic acid and a solvent comprising toluene may be heated to about 40 °C to about 60 °C. In a specific embodiment, a mixture of obeticholic acid and a solvent comprising toluene may be heated at about 45 °C to about 55 °C.

In one of the embodiments of step a), any physical form of obeticholic acid may be utilized, which may be crystalline or amorphous, for providing the solution of obeticholic acid in a solvent comprising toluene. In another embodiment of step a), any physical form of obeticholic acid may be utilized, which may be anhydrous or hydrate, for providing the solution of obeticholic acid in a solvent comprising toluene. In yet another embodiment, amorphous form of obeticholic acid and crystalline form C of Obeticholic acid as reported in the WO'097 application may be used in step a). In still another embodiment, crystalline forms A, D, F, G and I of obeticholic acid, as reported in the US' 082 application may be used in step a).

In one embodiment, the crystalline form VD3 of obeticholic acid may optionally be added to the solution of obeticholic acid in a solvent comprising toluene, as seed crystals.

Isolation of crystalline form VD3 of obeticholic acid in step c) may be performed by any technique known in the art. Specifically, crystalline form VD3 of obeticholic acid may be isolated from the mixture of step b) by filtration. Optionally, the crystalline form VD3 may be dried under suitable condition. Drying may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 80 °C and more specifically less than about 60 °C and most specifically at 40 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer.

The crystalline form VD3 of obeticholic acid may optionally be subjected to a particle size reduction procedure to produce desired particle sizes and distributions. Milling or micronization may be performed before drying, or after the completion of drying of crystalline form VD3 of obeticholic acid. Equipment that may be used for particle size reduction includes but not limited to ball mill, roller mill, hammer mill, and jet mill.

The crystalline form VD3 of obeticholic acid of the present application is stable and has excellent physico-chemical properties. The crystalline form VD3 of obeticholic acid of the present application may be easily formulated into a pharmaceutical composition comprising obeticholic acid.

Fifteenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.19, 6.37, 10.68, 15.98 and 18.75 ± 0.2° 2Θ. In embodiments, the present application provides crystalline form VD4 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 8.19 and 9.30 ± 0.2° 2Θ.

Sixteenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized by a PXRD pattern substantially as illustrated in Figure 7.

Seventeenth aspect of the present application relates to crystalline form VD4 of obeticholic acid characterized by DSC thermogram substantially as illustrated in Figure 8. In one embodiment of the present application relates to crystalline form VD4 of obeticholic acid characterized by d TGA thermogram substantially as illustrated in Figure 8.

Crystalline form VD4 of obeticholic acid may be toluene solvate. Toluene may be present in crystalline form VD4 of obeticholic acid in a range of about 1.0 to 3.0 % w/w. Specifically, toluene may be present in crystalline form VD4 of obeticholic acid is about 1.5 % w/w.

Eighteenth aspect of the present application relates to a process for preparing crystalline form VD4 of obeticholic acid comprising drying crystalline form VD3 of obeticholic acid at suitable temperature.

In one embodiment of the present application, drying of crystalline form VD3 of obeticholic acid may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 80 °C and more specifically less than about 60 °C and most specifically at 40 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer.

The crystalline form VD4 of obeticholic acid may optionally be subjected to a particle size reduction procedure to produce desired particle sizes and distributions. Milling or micronization may be performed before drying, or after the completion of drying of crystalline form VD4 of obeticholic acid. Equipment that may be used for particle size reduction includes but not limited to ball mill, roller mill, hammer mill, and jet mill.

The crystalline form VD4 of obeticholic acid of the present application is stable and has excellent physico-chemical properties. The crystalline form VD4 of obeticholic acid of the present application may be easily formulated into a pharmaceutical composition comprising obeticholic acid.

Nineteenth aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD4 of Obeticholic acid and one or more pharmaceutically acceptable excipient. Twentieth aspect of the present application relates to crystalline form VD5 of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 6.31, 8.88, 10.36, 14.37, 14.92, 15.81 and 16.58 ± 0.2° 2Θ. In embodiments, the present application relates to crystalline form VD5 of obeticholic acid characterized by its PXRD pattern having additional peaks located at about 4.35, 5.14, 7.53, 9.44, 10.00, 12.25 and 12.68 ± 0.2° 2Θ.

Crystalline form VD5 of obeticholic acid may be cyclohexane solvate. Cyclohexane may be present in crystalline form VD5 of obeticholic acid in a range of about 3.0 to 8.0 % w/w. Specifically, cyclohexane may be present in crystalline form VD5 of obeticholic acid in a range of about 5.0 to 6.5 % w/w.

a) mixing obeticholic acid in a solvent comprising cyclohexane;

b) optionally filtering the un-dissolved particles;

d) optionally, drying the isolated product at suitable temperature.

In embodiments of step a), the solvent may be a mixture of cyclohexane and an organic solvent. The organic solvent may include but not limited to, alcohols such as ethanol, isopropanol and the like; ketones such as acetone, methyl isobutyl ketone and the like; ethers such as diethyl ether, tetrahydrofuran and the like; esters such as ethyl acetate, propyl acetate and the like. Specifically, an organic solvent may be an alcohol solvent. More specifically, the alcohol solvent may be ethanol or isopropanol. In a specific embodiment, the solvent may be cyclohexane.

In one embodiment of step a), a mixture of obeticholic acid and a solvent comprising cuclohexane may be heated to about 40 °C to about 60 °C. In a specific embodiment, a mixture of obeticholic acid and a solvent comprising cyclohexane may be heated at about 45 °C to about 55 °C.

In one of the embodiments of step a), any physical form of obeticholic acid may be utilized, which may be crystalline or amorphous, for providing the solution of obeticholic acid in a solvent comprising cyclohexane. In another embodiment of step a), any physical form of obeticholic acid may be utilized, which may be anhydrous or hydrate, for providing the solution of obeticholic acid in a solvent comprising cyclohexane. In yet another embodiment, amorphous form of obeticholic acid, as reported in the WO'097 application may be used in step a). In still another embodiment, crystalline forms A, D, F, G and I of obeticholic acid, as reported in the US' 082 application may be used in step a).

In one embodiment, the crystalline form VD5 of obeticholic acid may optionally be added to the solution of obeticholic acid in a solvent comprising cyclohexane, as seed crystals.

Isolation of crystalline form VD5 of obeticholic acid in step c) may be performed by any technique known in the art. Specifically, crystalline form VD5 of obeticholic acid may be isolated from the mixture of step b) by filtration. Optionally, the crystalline form VD5 of obeticholic acid may be dried under suitable condition. Drying may be suitably carried out using any of an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer, and the like. The drying may be carried out at atmospheric pressure or above, or under reduced pressures, specifically at temperatures less than about 80 °C and more specifically less than about 60 °C and most specifically at 40 °C. The drying may be carried out for any time period required for obtaining a desired product quality, such as from about 5 minutes to about 24 hours, or longer.

The crystalline form VD5 of obeticholic acid may optionally be subjected to a particle size reduction procedure to produce desired particle sizes and distributions. Milling or micronization may be performed before drying, or after the completion of drying of crystalline form VD5 of obeticholic acid. Equipment that may be used for particle size reduction includes but not limited to ball mill, roller mill, hammer mill, and jet mill.

The crystalline form VD5 of obeticholic acid of the present application is stable and has excellent physico-chemical properties. The crystalline form VD5 of obeticholic acid of the present application may be easily formulated into a pharmaceutical composition comprising obeticholic acid.

Twenty third aspect of the present application relates to a pharmaceutical composition comprising crystalline form VD5 of obeticholic acid and one or more pharmaceutically acceptable excipient. Yet another aspect of the present application relates to a pharmaceutical composition comprising crystalline form VDl of obeticholic acid or crystalline form VDl of obeticholic acid or crystalline form VD3 of obeticholic acid or crystalline form VD4 of obeticholic acid or crystalline form VD5 of obeticholic acid and one or more pharmaceutically acceptable excipient. Crystalline form VD 1 of obeticholic acid or crystalline form VD 1 of obeticholic acid or crystalline form VD3 of obeticholic acid or crystalline form VD4 of obeticholic acid or crystalline form VD5 of obeticholic acid together with one or more pharmaceutically acceptable excipients of the present application may be formulated as: solid oral dosage forms such as, but not limited to, powders, granules, pellets, tablets, and capsules; liquid oral dosage forms such as, but not limited to, syrups, suspensions, dispersions, and emulsions; and injectable preparations such as, but not limited to, solutions, dispersions, and freeze dried compositions. Formulations may be in the forms of immediate release, delayed release, or modified release. Further, immediate release compositions may be conventional, dispersible, chewable, mouth dissolving, or flash melt preparations, and modified release compositions that may comprise hydrophilic or hydrophobic, or combinations of hydrophilic and hydrophobic, release rate controlling substances to form matrix or reservoir or combination of matrix and reservoir systems. The compositions may be prepared using any one or more of techniques such as direct blending, dry granulation, wet granulation, and extrusion and spheronization. Compositions may be presented as uncoated, film coated, sugar coated, powder coated, enteric coated, and modified release coated.

Pharmaceutically acceptable excipients that are useful in the present application include, but are not limited to: diluents such as starches, pregelatinized starches, lactose, powdered celluloses, microcrystalline celluloses, dicalcium phosphate, tricalcium phosphate, mannitol, sorbitol, sugar, and the like; binders such as acacia, guar gum, tragacanth, gelatin, polyvinylpyrrolidones, hydroxypropyl celluloses, hydroxypropyl methyl celluloses, pregelatinized starches, and the like; disintegrants such as starches, sodium starch glycolate, pregelatinized starches, crospovidones, croscarmellose sodium, colloidal silicon dioxide, and the like; lubricants such as stearic acid, magnesium stearate, zinc stearate, and the like; glidants such as colloidal silicon dioxide and the like; solubility or wetting enhancers such as anionic, cationic, or neutral surfactants; complex forming agents such as various grades of cyclodextrins and resins; and release rate controlling agents such as hydroxypropyl celluloses, hydroxymethyl celluloses, hydroxypropyl methylcelluloses, ethylcelluloses, methylcelluloses, various grades of methyl methacrylates, waxes, and the like. Other pharmaceutically acceptable excipients that are useful include, but are not limited to, film formers, plasticizers, colorants, flavoring agents, sweeteners, viscosity enhancers, preservatives, antioxidants, and the like.

The PXRD conditions for the measurement of PXRD peaks of the present application are as follows:

Range: 3° 2Θ to 40° 2Θ in conventional reflection mode

Instrument: PANalytical

Detector: Accelerator

Source: Copper K-alpha radiation (1.5418 Angstrom).

The DSC conditions for the measurement of endotherm of DSC thermogram of the present application are as follows:

Make: TA

Model: Discovery DSC

The TGA conditions for the measurement of endotherm of TGA thermogram of the present application are as follows:

Make: TA

Model: TGA Q-500

DEFINITIONS

The following definitions are used in connection with the present application unless the context indicates otherwise.

The terms "about," "general, 'generally," and the like are to be construed as modifying a term or value such that it is not an absolute. Such terms will be defined by the circumstances and the terms that they modify as those terms are understood by those of skill in the art. This includes, at very least, the degree of expected experimental error, technique error and instrument error for a given technique used to measure a value.

A name used herein to characterize a crystalline form should not be considered limiting with respect to any other substance possessing similar or identical physical and chemical characteristics, but rather it should be understood that these designations are mere identifiers that should be interpreted according to the characterization information also presented herein. All percentages and ratios used herein are by weight of the total composition and all measurements made are at about 25 °C and about atmospheric pressure, unless otherwise designated. All temperatures are in degrees Celsius unless specified otherwise. As used herein, the terms "comprising" and "comprises" mean the elements recited, or their equivalents in structure or function, plus any other element or elements which are not recited. The terms "having" and "including" are also to be construed as open ended. All ranges recited herein include the endpoints, including those that recite a range between two values. Whether so indicated or not, all values recited herein are approximate as defined by the circumstances, including the degree of expected experimental error, technique error, and instrument error for a given technique used to measure a value.

The term "optional" or "optionally" is taken to mean that the event or circumstance described in the specification may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

In general, a diffraction angle (2Θ) in powder X-ray diffractometry may have an error in the range of ± 0.2°. Therefore, the aforementioned diffraction angle values should be understood as including values in the range of about ± 0.2°. Accordingly, the present application includes not only crystals whose peak diffraction angles in powder X-ray diffractometry completely coincide with each other, but also crystals whose peak diffraction angles coincide with each other with an error of about ± 0.2°. Therefore, in the present specification, the phrase "having a diffraction peak at a diffraction angle (2Θ±0.2^°) of 19.6^°" means "having a diffraction peak at a diffraction angle (2Θ) of 19.4^° to 19.8^°. Although the intensities of peaks in the x-ray powder diffraction patterns of different batches of a compound may vary slightly, the peaks and the peak locations are characteristic for a specific polymorphic form. The relative intensities of the XRD peaks can vary depending on the sample preparation technique, crystal size distribution, various filters used, the sample mounting procedure, and the particular instrument employed. Moreover, instrument variation and other factors can affect the 2-theta values.

Certain specific aspects and embodiments of the present application will be explained in greater detail with reference to the following examples, which are provided only for purposes of illustration and should not be construed as limiting the scope of the disclosure in any manner. EXAMPLES

Example 1: Preparation of crystalline form VD1 of Obeticholic acid

Amorphous obeticholic acid ( 1 g) was dissolved in ethyl formate (20 mL) at 40 °C. The solution was filtered to separate the undissolved particles. The resulting clear solution was kept for slow evaporation at 25 °C for 24 hours. The precipitated solid was filtered under vacuum at 25 °C to provide the title compound.

Example 2: Preparation of crystalline form VD2 of Obeticholic acid

Crystalline form VD1 of obeticholic acid (0.5 g) was dried by using Air Tray Dryer (ATD) at 40 °C, for about 3 hours. The ATD temperature was slowly increased to 80 °C and dried at 80 °C for about 3 to 4 hours to provide the title compound.

Example 3: Preparation of crystalline form VD3 of Obeticholic acid

Obeticholic acid (1 g) was mixed with toluene (20 mL) at 50 °C and stirred for about 20 hours at 50 °C. The mixture was than cooled to 24 °C. The precipitated solid was filtered under vacuum at 24 °C. The resulting wet solid was kept in Air Tray Dryer (ATD) at 40 °C, dried for about 4 to 5 hours to provide the title compound.

Example 4: Preparation of crystalline form VD3 of Obeticholic acid

Obeticholic acid (2 g) was mixed with toluene (25 mL) at 25 °C. The mixture was heated to 55 °C and kept it for 2 hours. The reaction temperature was allowed to cool to 48 °C and kept it for about 20 hours. The mixture was cooled to 25 °C, precipitated solid was filtered and suck dried at 25 °C for 5 min. The resulting solid was kept in Air Tray Dryer (ATD) at 40 °C, dried for about 4-5 hours to provide the title compound.

Example 5: Preparation of crystalline form VD4 of Obeticholic acid Obeticholic acid as obtained in example 3 or Example 4 was kept in Air Tray Dryer (ATD) at 80 °C, dried for about 3 hours to provide the title compound.

Example 6: Preparation of crystalline form VD5 of Obeticholic acid

Amorphous obeticholic acid (400 mg) was mixed with cyclohexane (10 mL) and ethanol (109 mg) mixture at 30 °C. The solution temperature was raised to 50 °C, stirred for about 20 hours at 50 °C. The precipitated solid was filtered, resulting solid was kept in Air Tray Dryer (ATD) at 40 °C and dried for about 1 hours to provide the title compound.

Example 7: Preparation of crystalline form VD5 of Obeticholic acid

Amorphous obeticholic acid (400 mg) was suspended in cyclohexane (10 mL) and isopropyl alcohol (110 mg) mixture at 30 °C. The mixture was heated to 50 °C, stirred for about 20 hours at 50 °C. The precipitated solid was filtered, resulting solid was kept in Air Tray Dryer (ATD) at 40 °C and dried for about 1 hour to provide the title compound.

Example 8: Preparation of crystalline form VD2 of obeticholic acid

A mixture of amorphous obeticholic acid (40 g) and ethyl formate (800 mL) was heated to 45 °C and stirred for 1 hour to obtain a clear solution. The reaction mixture was slowly cooled to 4 °C and stirred for about 2 hours at the same temperature. The precipitated solid was filtered and suck dried. The resulting solid was dried in Air Tray Dryer (ATD) at 40 °C for about 3 hours. The ATD temperature is then raised to 80 °C without taking out the product from ATD and dried at the same temperture for about 3 hours to provide the title compound.

Example 9: Preparation of crystalline form VD2 of obeticholic acid

A mixture of amorphous obeticholic acid ( 16 g) and ethyl formate (240 mL) was heated to 43 °C and stirred for about 2 hour to obtain a clear solution. The reaction mixture was slowly cooled to 3 °C and stirred for about 2 hours at the same temperature. The precipitated solid was filtered and suck dried to obtain crystalline form VD 1 of obeticholic acid. The resulting crystalline form VD 1 of obeticholic acid was dried in Air Tray Dryer (ATD) at 40 °C for about 3 hours. The ATD temperature is then raised to 80 °C without taking out the product from ATD and dried at the same temperature for about 3 hours to provide the title compound.

Claims

WE CLAIM:

1. A crystalline form of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.15, 4.16, 6.29, 9.00, 11.03 and 15.43 ± 0.2° 2Θ.

2. The crystalline form of claim 1, further characterized by its powder X-ray diffraction (PXRD) pattern having additional peaks located at about 9.43, 9.89, 12.43 and 16.75 ± 0.2° 2Θ.

3. A process for preparing crystalline form of claim 1, comprising

a) dissolving obeticholic acid in a solvent comprising ethyl formate;

b) optionally filtering the un-dissolved particles;

d) optionally, drying the isolated product at suitable temperature.

4. A crystalline form of obeticholic acid characterized by its powder X-ray diffraction (PXRD) pattern having peaks at about 3.19, 6.37, 10.74, 16.00, 18.15 and 18.80 ± 0.2° 2Θ.

5. The crystalline form of claim 4, further characterized by its powder X-ray diffraction (PXRD) pattern having additional peaks located at about 7.75 and 9.30 ± 0.2° 2Θ.

6. The crystalline form of claim 4, further characterized by its powder X-ray diffraction (PXRD) pattern substantially as illustrated in Figure 2.

7. A process for preparing crystalline form of Obeticholic acid of claim 4, comprising drying crystalline form of obeticholic acid of claim 1 , at suitable temperature.

8. A process for preparing crystalline form of claim 4, comprising

a) dissolving obeticholic acid in ethyl formate;

b) cooling the reaction mass;

c) isolating the solid of step b); and

d) drying the solid of step c).

9. The mixture of obeticholic acid and ethyl formate in step a) of claim 8, is heated to a temperature at about 40-50 °C.

10. The reaction mixture of step b) of claim 8, is cooled to a temperature at about 4 °C.