FIELD OF THE INVENTION
The present invention relates to novel crystalline forms of obeticholic acid of Formula I
Formula I
wherein said forms are designated as Form MI, Form M-II and Form M-III.
The present invention further relates to a process for the preparation of Form M-I,
Form M-II and Form M-III of obeticholic acid.
BACKGROUND OF THE INVENTION
Obeticholic acid is a semi-synthetic bile acid analogue with the chemical name 6α-ethyl-chenodeoxycholic acid and is used for treating or preventing an FXR mediated disease or condition.
Obeticholic acid is known from US patent 7,138,390. The said patent discloses the process of preparation of obeticholic acid by using 6αEt-CDCA (3α7α-Dihydroxy-6α-ethyl-5ß-cholan-24-oic acid) which is generally prepared by chenodeoxycholic acid. It describes its isolation by means of column chromatography.
US 9,732,116 discloses Form C of obeticholic acid which is a crystalline form. Further, US 9,238,673 discloses an amorphous form of obeticholic acid designated as Form-1.
Further, US 2016/0108082 discloses crystalline Form A, C, D, G, F and I. This patent application states that crystalline Form G and F of obeticholic acid, are not suitable

for large scale production in the pharmaceutical industry due to lack of reproducibility
WO 2017/008773 discloses Form 1-2 and 1-3 wherein Form 1-2 is a monohydrate. The process for preparation of Form 1-2 includes dissolving obeticholic acid in butyl acetate under moderate reflux followed by leaving to cool down to the room temperature which is subsequently left to crystallize at room temperature. The process for preparation of Form 1-3 includes dissolving obeticholic acid in acetonitrile under moderate reflux. The clear solution was left to slowly cool down to the room temperature, seeded and subsequently left to crystallize at the room temperature.
WO 2017/115324 discloses crystalline forms a, P, y and 5 of obeticholic acid. The process for preparing crystalline Form a of obeticholic acid comprises of the steps of: a) providing obeticholic acid in n-heptane to obtain a reaction mixture, b) slurring the reaction mixture of step a) at room temperature, and c) isolating the crystalline Form a of obeticholic acid. The process for preparing crystalline Form P of obeticholic acid comprises of the steps of: a) providing obeticholic acid in toluene and heating at 70°C to obtain a solution, b) adding hexane to the solution of step (a) at about 25°C and stirring for about 12 hours, and c) isolating the crystalline Form P of obeticholic acid. The process for preparing crystalline Form y of obeticholic acid comprises of the steps of: a) providing obeticholic acid in a mixture of toluene and ethanol and heating at about 60°C to obtain a solution b) cooling the solution of step a) at about 25°C, and c) isolating the crystalline Form y of obeticholic acid. The crystalline Form-5 of obeticholic acid is prepared by slurring obeticholic acid in water followed by removal of solvent.
Further, WO 2016/107575 discloses Form A that is isolated from solvent system selected from ethyl acetate:^ n-heptane, methyl ethyl ketone: n-heptane, and chloroform: n-heptane.

CN 105985395 discloses crystalline form of obeticholic acid characterized by XRPD
wth-d-spaeing-pea^ 7.05, 5.35A°. This
patent application further discloses process of preparation of crystalline form of obeticholic acid by heating obeticholic acid at 60°C in an ester solvent.
CN 105859818 relates to ail alpha crystal form of obeticholic acid and apreparation method thereof. The preparation method comprises of fully dissolving obeticholic acid in a mixed solvent of toluene and another solvent selected from ethanol, tetrahydrofuran, and hexane followed by cooling the obtained obeticholic acid solution to precipitate out the alpha crystal form of the obeticholic acid.
CN 105859814 provides a crystal form of obeticholic acid, and a process for its preparation and a pharmaceutical composition thereof. The preparation method comprises of dissolving obeticholic acid in chloroform and precipitating the crystalline form of obeticholic acid by addition of n-heptane.
CN 105777836 discloses form I and form II of obeticholic acid wherein the preparation method for a crystal form I comprises the following steps: dissolving obeticholic acid in a solvent (toluene or acetic acid) under reflux, after complete
dissolution adding.a certain proportion of an anti-solvent (poor solvent), decreasing
i
a temperature, carrying out cooling so as to allow a crystal to be precipitated, and carrying out filtering and drying. The preparation method for a crystal form II comprises the following steps: dissolving obeticholic acid in an organic solvent (acetonitrile), carrying out refliixing, decreasing a temperature, carrying out cooling so as to allow a crystal to be precipitated, and carrying out filtering and drying.
CN 105175473 discloses Form I prepared by dissolving obeticholic acid in an organic solvent to form a solution, wherein the organic solvent is halogenated alkane or ester, and volatilizing the solution until all solvent is completely volatilized so as to obtain the obeticholic acid crystal form I.

Obeticholic acid that exists in different polymorphic forms such as anhydrous,
-hydr-ates-or-solvates7"hav^ units, possessing different physical
properties are known in the published literature. However, these known forms are either non-reproducible at large scale or do not possess high crystallinity. Therefore, there is always a need to develop a crystalline form having satisfactory physicochemical properties like stability, solubility and which can easily be formulated.
It is known that different polymorphs of the same drug possesses differences in solubility, melting points, density, stability, etc., thus affecting the stability of the drug in different degrees of uniformity, bioavailability, efficacy and safety.. Thus, there is carried out a comprehensive polymorph screening system to select the most suitable crystalline form which is an important part of the research and development.
Taking in consideration aforesaid, the present invention is focused towards the production of various crystalline forms of obeticholic acid which are stable and can easily be developed with high crystallinity and purity. Further, present invention is directed towards the development of the process for crystallization of obeticholic acid which is easy to handle and is reproducible, making the process suitable for large scale production. The crystal forms of the present invention has advantageous properties of being stable, consumable in technology and pharmaceutical formulation, and is suitable for being stored and used as a final product. In addition, the preparation method for the crystal form is simple and has low costs, and has important value in optimization and development of the medicine in the future.
OBJECT OF THE INVENTION
The main object ofythe present invention is to develop new crystalline forms of obeticholic acid.

Another object of the present invention is to develop an eco-friendly and simple
process-for-prodwtion--of-vmo "acid "wKcfi" aFe
reproducible at large scale production.
Another object of the present invention is to prepare stable and highly crystalline anhydrous forms of obeticholic acid which are stable and can be easily formulated.
SUMMARY OF THE INVENTION
The main aspect of the present invention is to provide new crystalline forms of obeticholic acid of Formula I
Formula I
*
Another aspect of the present invention is to provide a process of preparation of various crystalline forms of obeticholic acid.
Accordingly, the present invention provides crystalline Form M-I of obeticholic acid characterized by X-ray powder diffraction pattern comprising peaks at about 3.16, 9.76, 14.11, 15.87 and 21.79 ± O.2°0 with differential scanning calorimetry having endotherm peak at about 109.67°C
In other aspect, the present invention provides crystalline Form M-II of obeticholic acid characterized by X-ray powder diffraction pattern comprising peaks at about 3.19, 6.36, 10.76, 12.70 and 15.91 ± O.2°0 with differential scanning calorimetry having endotherm peak at about 112.08°C.

In another aspect, the present invention provides crystalline Form M-III of
\
obetieholic-acid characterized^^ pattern comprising peaks
at about 5.67, 8.94, 10.84, 22.18 and 25.80 ± 0.2°9 with differential scanning calorimetry having endotherm peak at about 89.78°C.
Another aspect of the present invention provides a process for preparation of Form M-I of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in a halogenated solvent;
b) heating to 30-60°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with halogenated solvent to obtain Form M-I of obeticholic acid.
Another aspect of the present invention provides a process for preparation of Form M-II of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in nitro ethane;
b) heating to 60-100°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with nitro ethane to obtain form M-II of obeticholic acid.
Another aspect of the present invention provides a process for preparation of Form M-III of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in an alcohol;
b) heating to 50-85°C to obtain a clear solution;
c) adding anti-solvent to get suspension;
d) cooling and keeping the suspension undisturbed for 16-34 hours; and
e) filtering and washing with anti-solvent to obtain form M-III of obeticholic acid.
Another aspect of the present invention provides crystalline form of obeticholic acid selected from Form M-I, Form M-II, Form M-III, and mixture thereof.

DETAILED DISCRIPTION
-Details-o£the-drawings:»
Fig. 1: XRPD diffractogram of crystalline obeticholic acid Form M-I Fig. 2: DSC thermogram of crystalline obeticholic acid Form M-I Fig. 3: XPRD diffractogram of crystalline obeticholic acid Form M-II Fig. 4: DSC thermogram of crystalline obeticholic acid, Form M-II Fig. 5: XPRD diffractogram of crystalline obeticholic acid Form M-III Fig. 6: DSC thermogram of crystalline obeticholic acid Form M-III
The present invention will now be explained in details. While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention as defined by the appended claims.
The steps of a method may be providing more details that are pertinent to understanding the embodiments of the present invention and so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
Further characteristics and advantages of the process according to the invention will result from the description herein below of preferred exemplary embodiments, which are given as indicative and non-limiting examples.
All ranges recited herein include the endpoints, including those that recite a range "between" two values. Terms such as "about", "substantially" and the like are to be construed as modifying a term or value such that it is not an absolute. 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.

The main aspect of the present invention is to provide new crystalline forms of
-obetieholic-acid:
Accordingly, in one embodiment the present invention provides crystalline forms of. obeticholic acid, wherein the crystalline form is selected from Form M-l, Form M-II, Form M-III or mixture thereof, and wherein:
a) Form M-I has an X-ray powder diffraction pattern comprising peaks at about 3.16, 9.76, 14.11, 15.87 and 21.79 ± O.2°0 with differential.scanning calorimetry having endotherm peak at about 109.64°C; /
b) Form M-II has an X-ray powder diffraction pattern comprising peaks at about 3.19, 6.36, 10.76,, 12.70 and 15.91 ± 0.2°9 with differential scanning calorimetry having endotherm peak at about 112.08°C; and
. c) Form M-III has an X-ray powder diffraction pattern comprising peaks at about 5.67, 8.94, 10.84, 22.18 and 25.80 ± O.2°0 with differential scanning calorimetry having endotherm peak at about 89;78°C.
In another embodiment, the crystalline Forms M-I, M-II and M-III are anhydrous in nature.
In preferred embodiment, the present invention provides crystalline Form M-I of obeticholic acid characterized by X-ray powder diffraction pattern comprising peaks at about 3.16, 9.76, 14.11, 15.87 and 21.79 ± 0.2°9 with differential scanning calorimetry having endotherm peak at about 109.67°C
In other preferred embodiment, the crystalline Form M-I is characterized by X-ray powder diffraction pattern comprising peaks at about 3.16, 6.32,7.71, 8.17, 8.82, 9.47,9.76, 10.85, 12.13, 12.54,14.11, 15.87, 16.50, 18.32, 20.24, 21.79 ±0.2°9.
f
In another embodiment, the Form M-I is characterized by diffraction scanning calorimetry (DSC) with an onset temperature of about 102.78°C. It is further characterized by DSC >vith an endotherm peak at about 109.64°C.

In-oneanother-embodimentrthepresennnvehtion provides a process ior preparaxion
of Form M-I of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in a halogenated solvent;
b) heating to 30-60°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with halogenated solvent to obtain Form M-I of obeticholic acid.
In a preferred embodiment, the present invention provides a process for preparation of Form M-I of obeticholic. acid characterized by X-ray powder diffraction pattern comprising peaks at about 3.16, 9.76, 14.11, 15.87 and 21.79 ± O.2°0, wherein the process comprising of:
a) adding obeticholic acid in a halogenated solvent;
b) heating to 30-60°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with halogenated solvent to obtain Form M-I of obeticholic acid.
In another preferred embodiment, the heating of solution of obeticholic .acid in halogenated solvent in step b) is performed at a temperature in the range of 35-50°C and most preferably at 35-45°C.
In another embodiment, the halogenated solvent is selected from the group comprising of methylene dichloride, dichlorobenzene, ethylene dichloride, chloroform, and carbon tetrachloride.
In further embodiment, the cooling of the clear solution of obeticholic acid in
halogenated solvent is carried out preferably at room temperature to -5°C.
v.

-In other embodiment, the present invention provides crystalline Form M-II of __obeticholic-aGid characterized"by X^ray^wderlirffraction pattern comprising peaks at about 3.19, 6.36, 10.76, 12.70 and 15.91 ± O.2°0vwith differential scanning calorimetry having endotherm peak at about 112.08°C.
In a preferred embodiment, the present invention provides Form M-II of obeticholic acid which is characterized by X-ray powder diffraction pattern comprising peaks at 3.19, 4.08, 6.36, 7.78, 8.26, 8.85, 9.50, 10.76, 12.70, 14.04, 15.50, 15.91, 17.01, 18.72, 19.08, 20.34, 20.79, 21.66, 24.62 ± 0.2°0.
In another preferred embodiment, Form M-II is characterized by diffraction scanning calorimetry (DSC) with an onset temperature of about 105.03°C. It is further characterized by DSC at about 112.08°C.
In one another embodiment, the present invention provides a process for preparation of Form M-II of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in nitro ethane;
b) heating to 60-100°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with nitro ethane to obtain form M-II of obeticholic acid.
In a preferred embodiment, the present invention provides process for preparation of Form M-II of obeticholic acid characterized by X-ray powder diffraction pattern comprising peaks at about 3.19, 6.36, 10.76, 12.70 and 15.91 ± 0.2°9, wherein the process comprising of:
a) adding obeticholic acid in nitro ethane;
b) heating to 60-100°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with nitro ethane to obtain form M-II of obeticholic acid.

In another embodiment, the heating of solution of obeticholic acid in nitro ethane in
step-(-b)4s-performed-at atempefatuf e in therange of60-100°C and preferably at 65-
85°C and most preferably at 70-80°C.
In further embodiment, the cooling of the clear solution as obtained from step (b) mentioned above is preferably performed between room temperature to -5°C, and most preferably at room temperature.
In another embodiment, the present invention provides crystalline Fornr M-III of obeticholic acid characterized by X-ray powder diffraction pattern comprising peaks at about 5.67, 8.94, 10.84, 22.18 and 25.80 ± O.2°0 with differential scanning calorimetry having endotherm peak at about 89.78°C.
In one of the another preferred embodiments, the present invention provides Form M-III of obeticholic acid which is characterized by X-ray powder diffraction pattern comprising peaks at about 3.16, 4.11, 4.63, 5.67, 6.33, 7.81, 8.23, 8.94, 9.17, 9.42, 9.86, 10.84, 11.19, 11.43, 12.14, 12.38, 12.51, 12.68, 13.31, 13.58, 14.06, 14.55, 15.00, 15.26, 15.51, 15.88, 16.54, 17.11, 17.64, 17.90, 18.46, 18.89, 19.13, 20.33, 20.71, 21.14, 21.69, 22.18, 22.85, 23.54, 24.43, 24.95, 25.41, 25.80, 26.77 ± O.2°0.
In preferred embodiment, Form M-III is characterized by diffraction scanning calorimetry (DSC) with an onset temperature of about 83.47°C. It is further characterized by DSC with an endotherm peak at about 89.78°C.
In one another embodiment, the present invention provides a process for preparation of Form M-III of obeticholic acid wherein the process comprising of:
a) adding obeticholic acid in an alcohol;
b) heating to 50-85°C to obtain a clear solution;
c) adding anti-solvent to get suspension;
d) cooling and keeping the suspension undisturbed for 16-34 hours; and
e) filtering and washing with anti-solvent to obtain form M-III of obeticholic acid.

_In.a_preferred-embodiment7-the-present"invention provides process of preparation of Form M-III of obeticholic acid characterized by peaks at about 5.67, 8.94, 10.84, 22.18 and 25.80 ± 0.2°0, wherein the process comprising of:
a) adding obeticholic acid in an alcohol;
b) heating to 50-85°C to obtain a clear solution;
c) adding anti-solvent to get suspension;
d) cooling and keeping the suspension undisturbed for 16-34 hours; and
e) filtering and washing with anti-solvent to obtain Form M-III of obeticholic acid.
In another embodiment, heating of the solution of obeticholic acid in alcohol in step b) is performed at a temperature in the range of 50-85°C and preferably at 55-70°C and most preferably at 55-60°C.
In another embodiment, the alcohol s.olvent used for dissolving obeticholic acid in step a) is selected from the group comprising of iso amyl alcohol, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, and neo pentyl alcohol. Moreover, the anti-solvent used for precipitation of crystalline Form M-III in step c) and washing .of isolated crystalline Form M-III in step e) are selected from non-polar solvents, selected from the group comprising of heptane, hexane, isooctane, isopropyl ether, pentane, and octane.
In further embodiment, the obeticholic acid used for preparation of polymorphs . selected from Form M-I, Form M-II and Form M-III can be prepared by any of the conventional methods. Moreover, the obeticholic acid used for preparation of crystalline Form M-I, Form M-II and Form M-III, can be amorphous or crystalline in nature.
In still another embodiment, the Form M-I, Form M-II and Form M-III as prepared by the process of the present invention are stable and can easily be formulated.

In yet another embodiment, the present invention provides a composition comprising
obeticholic-aeid-polymorph and pharmaceutically acceptable excipients wherein said
obeticholic acid polymorph is selected from Form M-I, Form M-II and Form M-III as obtained from the present invention.
In other embodiment, the crystalline forms of obeticholic acid as obtained from the present invention is isolated with purity of 98% or above and preferably, 99% or above.
In preferred embodiment, the crystalline forms of obeticholic acid is selected from Form M-I, Form M-II, Form M-III, and mixture thereof.
In one embodiment, the present invention relates to a crystalline forms of obeticholic acid selected from Form M-I, M-II, M-III; wherein any of the crystalline forms contains a total of less than about 3% w/w of total impurities wherein each impurity selected from Hthocholic acid, deoxycholic acid, nutriacholic acid or mixture thereof is less than about 0.15%w/w. In preferred embodiment, the total impurities is less than about 1.0% w/w.
In another embodiment, the crystalline forms of obeticholic as prepared by the process of the present invention is characterized by particle size distribution wherein, d90 is 0.1 µm to 200µm.
In another embodiment, the crystalline forms of obeticholic acid obeticholic as prepared by the process of the present invention is characterized by particle size distribution wherein, d90 is 2.0 µm to 150µm.
The present invention will now be explained in details through experimentations. However, the examples are provided as one of the possible way to practice the invention and should not be considered as limitation of the scope of the invention.

EXAMPLES:
1. Preparation of Form M-I of obeticholic acid
Charged 2g of obeticholic acid in 50 ml of methylene dichloride. Heated the solution at 40°C under stirring to get clear solution. Cooled the clear solution to room temperature and left the solution undisturbed till precipitation. Filtered the precipitates, washed with methylene dichloride and dried to get 1.6g of crystalline Form M-I.
2. Preparation of Form M-II of obeticholic acid 7
Charged lg of obeticholic acid in 15 ml of nitro ethane and heated the solution to 70°C. Stirred the solution under heating till clear solution is obtained. Cooled the solution to room temperature and left undisturbed till precipitation. Filtered the precipitates, washed with nitro ethane and dried to get 0.7g of crystalline Form M-II.
3. Preparation of Form M-III of obeticholic acid
Charged lg of obeticholic acid in 2ml of isoamyl alcohol and heated to 60°C under stirring till clear solution is obtained. Added 8 ml heptane as anti-solvent to get a suspension. Cooled the suspension to room temperature and the reaction mass was left to stand overnight at room temperature. Filtered and washed the precipitates with heptane followed by drying at 50°C to obtain 0.7g of crystalline Form M-III.

WE CLAIM
1. A crystalline form of obeticholic acid, wherein the crystalline form is selected from
Form M-1, Form M-II, Form M-III or mixture thereof, and wherein;
s
a) Form M-I has an X-ray powder diffraction pattern comprising peaks at about 3.16, 9.76, 14.11, 15.87 and 21.79 ± O.2°0 with differential scanning calorimetry having endotherm peak at about 109.67°C;
b) Form M-II has an X-ray powder diffraction pattern comprising peaks at about. 3.19, 6.36, 10.76, 12.70 and 15.91 ± 0.2°θ with differential scanning calorimetry having endotherm peak at about 112.08°C; and
c) Form M-III has an X-ray powder diffraction pattern comprising peaks at about 5.67, 8.94, 10.84, 22.18 and 25.80 ± 0.2°θ with differential scanning calorimetry having endotherm peak at about 89.78°C.
2. A process for preparation of Form M-I of obeticholic acid wherein the process
comprising of:
a) adding obeticholic acid in a halogenated solvent;
i
b) heating to 30-60°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with halogenated solvent to obtain Form M-I of obeticholic acid.

3. The process as claimed in claim 2, wherein said halogenated solvent is selected from the group comprising of methylene dichloride, dichlorobenzene, ethylene dichloride, chloroform, and carbon tetrachloride.
4. A process for preparation of Form M-II of obeticholic acid wherein the process, comprising of:

a) adding obeticholic acid in nitro ethane;
b) heating to 60-100°C to obtain a clear solution;
c) cooling and keeping the clear solution undisturbed for 16-34 hours; and
d) filtering and washing with nitro ethane to obtain form M-II of obeticholic acid.

5. The process as claimed in claim 4, wherein said cooling in step (c) is carried out at a temperature in the range of ambient temperatures to -5°C.
6. A process for preparation of Form M-III of obeticholic acid wherein the process
comprising of:
a) adding obeticholic acid in an alcohol;
b) heating to 50-85°C to obtain a clear solution;
c) adding anti-solvent to get suspension;
d) cooling and keeping the suspension undisturbed for 16-34 hours; and
e) filtering and washing with anti-solvent to obtain form M-III of obeticholic acid.

7. The process as claimed in claim 6, wherein said alcohol solvent used in step a) is selected from the group comprising of iso amyl alcohol, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, and neo pentyl alcohol.
8. The process as claimed in claim 6, wherein said anti-solvent is selected from the group comprising of heptane, hexane, isooctane, isopropyl ether, pentane, and octane.
9. The crystalline of obeticholic acid as claimed in claim 1, wherein said crystalline form is used for preparing a composition comprising at least one pharmaceutically acceptable excipients along with the crystalline form of obeticholic acid selected from Form M-l, Form-II, or Form-Ill.
10. The crystalline of obeticholic acid as claimed in claim 1, wherein either of
crystalline Forms M-I, M-II, or M-III is isolated with purity of 98% or above.