FIELD OF THE INVENTION

The present invention relates to novel salts of Aramchol with an improved water solubility, physicochemical stability and dissolution characteristics. In particular, the present invention relates to sodium, potassium, magnesium, calcium and zinc salts of Aramchol and the process for the preparation thereof. Further, the present invention relates to crystalline form of each of the individual novel salt of Aramchol.

BACKGROUND OF THE INVENTION

Aramchol, having a chemical name 3P-arachidylamido-7a,12a-dihydroxy-5P-cholan-24-oic acid is represented as Formula I with the structure as follows:

Aramchol is an amide conjugate of arachidic acid and 3-aminocholic acid, effective in reducing liver fat content as well as improving metabolic parameters associated with fatty liver disease. It belongs to a novel family of synthetic Fatty- Acid / Bile- Acid Conjugates (F ABACs) and is being developed as a potentially disease modifying treatment for the fatty liver disease and Nonalcoholic steatohepatitis (NASH).

WO 2015083164 (the WO’ 164 patent) discloses various amine salts of the Aramchol for example, salts with amino alcohols, amino sugars or amino acids, a pharmaceutical composition comprising said salts, methods for their preparation and use thereof in medical treatment. Aramchol meglumine salt disclosed in the WO’ 164 patent has significantly greater solubility than free base. Aramchol meglumine is under clinical investigation for NonAlcoholic SteatoHepatitis (NASH) and clinical studies in healthy volunteers demonstrated that administration of Aramchol meglumine salt doubled the systemic exposure of Aramchol.

In the WO’ 164 patent around 30 salts were screened to improve water solubility of the Aramchol. Water solubility studies of screened Aramchol salts summarized in the Table 2 of the WO’ 164 patent. However, only few salts were found to have improved the solubility of the Aramchol, for example A-methylglucamine (meglumine), lysine or tromethamine salts. This indicates that except meglumine salt, the all other salts disclosed in the WO’ 164 patent has low water solubility. Also, Table 3 of the WO’ 164 patent indicates that in many cases there was no stable salt formation with amine.

In view of the above, there is a need for new, easy to prepare and readily available pharmaceutically acceptable salts of Aramchol with an improved water solubility, physicochemical stability and the dissolution characteristics.

Therefore, the objective of the present invention is to provide new salts of Aramchol with an improved water solubility, physicochemical stability, and dissolution characteristics using a simple, cost effective, and industrially scalable process.

OBJECTIVES OF THE INVENTION

The main object of the present invention is to provide novel salts of Aramchol which is structurally represented as below. Wherein, M ⁺ represents a cation selected from sodium, potassium, calcium, magnesium and zinc.

Another object of the present invention is to provide a cost effective, simple, and industrially scalable process to produce a pure and high yield of novel salts of Aramchol.

Another object of the present invention is to provide the crystalline form of the novel salts of Aramchol.

Yet another object of the present invention is to provide a pharmaceutical composition comprising novel salts of Aramchol and pharmaceutically acceptable excipients, wherein the water solubility, physicochemical stability and dissolution characteristics of the Aramchol salts is improved, thereby rendering it more suitable for use in the pharmaceutical composition.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides novel salts of Aramchol structurally represented as below.

Wherein, M ⁺ represents a cation selected from sodium, potassium, calcium, magnesium and zinc.

In another embodiment, the present invention provides the process for the preparation of novel salts of Aramchol of the present invention comprising steps of: a) providing a mixture comprising Aramchol and a salt or alcoholic solution of a salt or a base in presence of a suitable solvent; b) stirring and optionally heating the reaction mass; c) filtering the obtained reaction mass and adding a second solvent to the reaction mass; d) isolating the corresponding salt of Aramchol from the precipitate obtained from step (c) by filtration, washing and drying under vacuum.

In yet another aspect, the present invention provides a process for the preparation of novel salts of the present invention using above disclosed general process.

In one aspect, the present invention provides the crystalline form of each of the individual novel salt of Aramchol characterized by XRPD, DSC and TGA as disclosed in the present invention.

In another aspect, the present invention provides a pharmaceutical composition comprising novel salts of Aramchol of the present invention and pharmaceutically acceptable excipients, wherein the water solubility, physicochemical stability and dissolution characteristics of the Aramchol salts of the present invention is improved, thereby rendering it more suitable for use in the pharmaceutical composition.

BRIEF DESCRIPTION OF DRAWINGS OF THE INVENTION

Fig- 1 illustrates the XRPD pattern of Crystalline sodium salt of Aramchol, obtained by process of Example 1.

Fig- 2 illustrates the XRPD pattern of Crystalline potassium salt of Aramchol, obtained by process of Example 2.

Fig- 3 illustrates the Differential Scanning Calorimetry (DSC) of sodium salt of Aramchol, obtained by process of Example 1.

Fig. 4 illustrates the Differential Scanning Calorimetry (DSC) of potassium salt of Aramchol, obtained by process of Example 2.

Fig. 5 illustrates the Differential Thermogravimetric Analysis (TGA) of sodium salt of Aramchol, obtained by process of Example 1.

Fig. 6 illustrates the Differential Thermogravimetric Analysis (TGA) of potassium salt of Aramchol, obtained by process of Example 2. DETAILED DESCRIPTION OF THE INVENTION

The above and other objects of the present invention are achieved by the novel salts of the of the present invention.

The present invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In an embodiment, the present invention provides novel salts of Aramchol structurally represented as below.

Wherein, I T represents a cation selected from sodium, potassium, calcium, magnesium and zinc.

In an embodiment, the present invention provides the general process for the preparation of novel salts of Aramchol of the present invention, comprising steps of: a) providing a mixture comprising Aramchol and a salt or alcoholic solution of a salt or a base in presence of a suitable solvent; b) stirring and optionally, heating the reaction mass; c) filtering the obtained reaction mass and adding a second solvent to the reaction mass; d) isolating the corresponding salt of Aramchol from the precipitate obtained from step c) by filtration, washing and drying under vacuum. In a preferred embodiment, the present invention provides sodium and potassium salts of Aramchol prepared using the above described general process of the present invention.

The process of the preparation of sodium or potassium salt of Aramchol of the present invention is represented schematically in the scheme 1 as given below.

Scheme 1:

The inventors of the present invention, after extensive experimentation have found that novel salts of Aramchol have good water solubility, chemical stability and dissolution characteristics. Particularly, the potassium salt of Aramchol found to have highest water solubility and good chemical stability as compared to the other salts of the present invention. Additionally, novel salts of Aramchol of the present invention are pharmaceutically acceptable and easy to prepare using readily available raw materials

In an embodiment, the alcoholic solution of the salt used in the present invention is prepared using a solvent selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n- butanol, and isobutanol.

In an embodiment, the salt used for preparation of sodium or potassium salt of Aramchol is a base of sodium or potassium. In an embodiment, the base of sodium is selected from sodium hydroxide, sodium t-butoxide. Preferably, the base is sodium hydroxide. In another embodiment, the base of potassium is selected from potassium hydroxide, potassium t-butoxide. Preferably, the base is potassium hydroxide.

In an embodiment, the present invention provides a magnesium, calcium and zinc salt of Aramchol prepared using the above described general process of the present invention. In an embodiment, the alkali salt of Aramchol is used as starting material for the preparation of a magnesium, calcium and zinc salt of Aramchol.

In an embodiment, the alkali salt of Aramchol is selected from sodium and potassium salt.

The process for the preparation of a magnesium, calcium and zinc salt Aramchol of the present invention is represented schematically in the scheme 2 as given below.

In an embodiment, the magnesium salt is selected from the group consisting of magnesium chloride hexahydrate, magnesium sulphate, magnesium acetate. Preferably, the magnesium salt is magnesium chloride hexahydrate.

In an embodiment, the calcium salt is selected from the group consisting of calcium chloride, calcium sulphate, calcium acetate. Preferably, the calcium salt is calcium chloride.

In an embodiment, the zinc salt is selected from the group consisting of zinc chloride, zinc sulphate, zinc phosphate, zinc citrate. Preferably, the zinc salt is zinc chloride.

In an embodiment, the suitable solvent used for the preparation of individual salts disclosed in the present invention is selected from the group consisting of methanol, n-butanol, t-butanol, acetonitrile, isopropyl alcohol (IP A), isopropyl acetate, ethyl acetate or a mixture thereof. Preferably, the solvents are selected from methanol and n-butanol.

In an embodiment, the second solvent used for the isolation of each individual salts disclosed in the present invention is selected from the group consisting of methanol, n-butanol, t-butanol, acetonitrile, isopropyl alcohol, isopropyl acetate, hexane, toluene, heptane, chloroform, butanone, ethyl acetate, butyl acetate, t-butyl acetate, cyclohexanone or a mixture thereof. Preferably, the solvents are selected from methanol, acetonitrile and isopropyl alcohol or mixture thereof.

In an embodiment, the reaction for the preparation of individual salts of Aramchol can be carried out at a temperature ranging from 30-55 °C. In an embodiment, the reaction for the preparation of individual salts of Aramchol preferably can be carried out at a temperature range from 40-55 °C.

In a preferred embodiment, the sodium salt of the present invention is prepared by the process comprising steps of: a) mixing methanolic sodium hydroxide solution in methanol and Aramchol in isopropyl alcohol at a temperature ranging from 35-40 °C and stirring for 15 min; b) cooling the resultant reaction mass to 0-30 °C and filtration followed by washing with isopropyl alcohol; c) adding acetonitrile in the resultant reaction mass and stirring for 60 min; d) filtrating obtained solid precipitate and isolating the corresponding sodium salt of Aramchol followed by washing and drying under vacuum.

In a preferred embodiment, the potassium salt of the present invention prepared by the process comprising steps of: a) mixing methanolic potassium hydroxide solution in methanol and Aramchol in isopropyl alcohol at a temperature ranging from 35-40 °C and stirring for 15 min; b) cooling the resultant reaction mass to 0-30 °C and filtration followed by washing with isopropyl alcohol; c) adding acetonitrile in the resultant reaction mass and stirring for 60 min; d) filtrating obtained solid precipitate and isolating the corresponding potassium salt of Aramchol followed by washing and drying under vacuum.

In a preferred embodiment, the magnesium salt of the present invention prepared by the process comprising steps of: a) mixing methanolic sodium hydroxide solution in methanol and Aramchol in isopropyl alcohol at a temperature ranging from 50-55°C then addition of magnesium chloride; b) cooling the resultant reaction mass to a temperature ranging from 25-30°C followed by stirring; c) adding acetonitrile in the resultant reaction mass and stirring for 60 min; d) filtrating obtained solid precipitate and isolating the corresponding magnesium salt of Aramchol followed by washing and drying under vacuum.

In a preferred embodiment, the calcium salt of the present invention prepared by the process comprising steps of: a) mixing methanolic sodium hydroxide solution in methanol and Aramchol in isopropyl alcohol at a temperature ranging from 50-55°C then addition of calcium chloride dihydrate; b) cooling the resultant reaction mass to a temperature ranging from 25-30°C followed by stirring; c) adding acetonitrile in the resultant reaction mass and stirring for 60 min; d) filtrating obtained solid precipitate and isolating the corresponding calcium salt of Aramchol followed by washing and drying under vacuum.

In an embodiment of the present invention, the present invention provides a crystalline form of sodium and potassium salt of the Aramchol prepared by the process of the present invention.

In another embodiment of the present invention, the sodium salt of Aramchol prepared by the process of the present invention is characterized by an X-ray Powder Diffraction (XRPD) pattern as depicted in Fig.1, a Differential Scanning Calorimetry (DSC) as depicted in Fig. 3, and a Thermal Gravimetric Analysis (TGA) as depicted in Fig. 5.

In specific embodiment of the present invention, the sodium salt of Aramchol prepared using process of the present invention is characterized by XRPD pattern having peaks with two-theta positions at about 4.6± 0.2°, 6.2± 0.2°, 7.6± 0.2°, 9.3± 0.2°, 11.6± 0.2°, 14.4± 0.2°, 20.3± 0.2°, 20.9± 0.2° and 23.3 ± 0.2° as depicted in Fig. 1.

In another embodiment of the present invention, the potassium salt of Aramchol prepared using process of the present invention is characterized by an X-ray Powder Diffraction (XRPD) pattern as depicted in Fig. 2, a Differential Scanning Calorimetry (DSC) as depicted in Fig. 4, and a Thermal Gravimetric Analysis (TGA) as depicted in Fig. 6. In specific embodiment of the present invention, the potassium salt of Aramchol prepared by the process of the present invention is characterized by X-ray powder diffraction (XRPD) pattern having peaks with two-theta positions at about at 6.1± 0.2°, 7.6± 0.2°, 8.4± 0.2°, 11 ,6± 0.2°, 14.4± 0.2°, 16.9± 0.2°, 20.9± 0.2° and 23.3± 0.2° as depicted in Fig. 2.

In another embodiment, the sodium, potassium, magnesium, calcium and zinc salts Aramchol of the present invention may be present as amorphous powder.

The crystalline and amorphous forms as provided herein may be characterized by using a number of methods known to a person of skilled in the art, including X-ray powder diffraction (XRPD), microscopy (e.g Scanning Electron Microscopy (SEM), thermal analysis (e.g Differential Scanning Calorimetry (DSC)), thermal gravimetric analysis (TGA), and hot-state microscopy and spectroscopy (e.g infrared, Raman, solid-state nuclear magnetic resonance). The purity of the crystalline form provided herein may be may be determined by standard analytical methods, such as thin layer chromatography (TLC), gel electrophoresis, gas chromatography, high performance liquid chromatography (HPI..C), and mass spectrometry (MS).

In another embodiment, there is provided novel salts of Aramchol having a particle size distribution having D(10) of about 10 pm or less, D(50) of about 25 pm or less and D(90) of about 100 pm or less. The particle size and size distribution may be determined by conventional methods, such as laser light scattering technique.

In another embodiment, the present invention provides a pharmaceutical composition comprising crystalline form of novel salts of the present invention and pharmaceutically acceptable excipients, wherein the water solubility, physicochemical stability and the dissolution characteristics of the Aramchol salts is improved and is rendered more suitable for use in a pharmaceutical composition.

In another embodiment, the compositions containing novel salts of Aramchol are useful in reducing cholesterol levels in the blood or treating fatty liver, or for the treatment of Non Alcoholic SteatoHepatitis (NASH) or any disease that its treatment may benefit from modulating cholesterol or lipid balance. The pharmaceutical composition may be in the form of tablets, pills, capsules, pellets, granules, powders, lozenges, sachets, cachets, patches, elixirs, suspensions, dispersions, emulsions, solutions, syrups, aerosols, ointments, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders.

The pharmaceutically acceptable excipients may be selected from, but not limited to, disintegrants, lubricants, diluents, binders, preservatives, suspending agents, sweetening agents, glidants, coloring agents, flavoring agents, surfactants and the like.

The workability of the present invention has been exemplified below based on some non-limiting illustrations. Certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.

EXAMPLES

Example 1: Process for the preparation of Aramchol sodium salt

Prepared a methanolic Sodium hydroxide solution (1.1 mole) in 50 mL methanol at 35-40°C. Charged Aramchol (25 gm, 1.0 mole) and isopropyl alcohol (75 ml), stirred for 15 min and filtered through filter paper washed with 10 ml isopropyl alcohol. The resultant reaction mass was cooled to 20-30°C and addition of 125 ml acetonitrile. Stirred the reaction mass for 60 min. The obtained solid was filtered and washed with acetonitrile: isopropyl alcohol: methanol (10:6:4 mL) and dried under vacuum below 35°C. Output: 22.5 g; yield: 87%; HPLC purity: 99.26%. The obtained solid was subjected to XRPD, DSC and TGA studies and the results are shown in Fig. 1, Fig. 3 and Fig. 5 respectively.

Example 2: Process for the preparation of Aramchol potassium salt

Prepared a methanolic potassium hydroxide solution (1.1 mole) in 50 mL methanol at 35-40°C. Charged Aramchol (25 gm, 1.0 mole) and 75 ml isopropyl alcohol, stirred for 15 min and filtered through filter paper washed with 10 ml isopropyl alcohol. The resultant reaction mass cooled to 20-30°C and addition of 125 ml acetonitrile. Stirred the reaction mass for 60 min. the s obtained solid product was filtered and washed with acetonitrile: isopropyl alcohol: methanol (10:6:4 mL) and dried under vacuum below 35°C. Output: 21.3 g; yield: 81%; HPLC purity: 99.33%. The obtained solid was subject to XRPD, DSC and TGA studies and the results are shown in Fig.2, Fig. 4 and Fig. 6 respectively.

Example 3: Process for the preparation of Aramchol magnesium salt

Aramchol (5g, 1 mole eq.) was dissolved in isopropyl alcohol (25 mL) at 50-55°C. Added methanolic sodium hydroxide (1.0 mole eq) solution then added Magnesium chloride (0.5 mole eq.). The resultant solution was cooled while stirring at 25-30°C and added 20 ml Acetonitrile to precipitate the product. The obtained solid product was filtered and washed with acetonitrile (5 mL) and dried under vacuum below 50°C. Output: 5 g; yield: 96%

Example 4: Process for the preparation of Aramchol calcium salt

Aramchol (5g, 1 mole eq.) was dissolved in isopropyl alcohol (25 mL) at 50-55°C. Added methanolic sodium hydroxide (1.0 mole eq) solution then addition of calcium chloride dihydrate (0.5 mole eq.). The resultant solution was cooled while stirring at 25-30°C and added 20 ml Acetonitrile to precipitate the product. The obtained solid product was filtered and washed with acetonitrile (10 mL) and dried under vacuum below 50°C. Output: 4.6 g; yield: 87%;

Example 5: Process for the preparation of Aramchol Zinc salt

Aramchol (5g, 1 mole eq.) was dissolved in isopropyl alcohol (25 mL) at 50-55°C. Added methanolic sodium hydroxide (1.0 mole eq) solution then addition of zinc chloride (0.5 mole eq.). The resultant solution was cooled while stirring at 25-30°C and added 20 ml Acetonitrile to precipitate the product. The obtained solid product was filtered and washed with acetonitrile (10 mL) and dried under vacuum below 50°C to obtain a crystalline powder.