The invention provides Saxagliptin Schiff bases, polymorphs of Saxagliptin and ( 1 S,3S,5S)-2-[(2S)-2-propan-2-y lideneamino-2-(3-hydroxy- 1 -adamanty l)acetyl]- 2-azabicyclo[3.1.0]hexane-3-carbonitrile, processes for preparing Saxagliptin hydrates, and pharmaceutical compositions thereof.

The present invention relates to a novel salt of perindopril, namely the paratoluene sulfonic acid salt. The present invention also relates to an amorphous form of the perindopril paratoluene sulfonic acid salt. The invention further relates to processes for the preparation of the novel salt and the amorphous form thereof. The invention also relates to pharmaceutical compositions comprising the perindopril tosylate for the treatment of hypertension and heart failure.

Solid state forms of Sitagliptin salts, processes for preparing the solid state forms, and pharmaceutical compositions thereof, are provided.

The present invention provides crystalline forms of Rosiglitazone hydrobromide, methods of their preparation, as well as pharmaceutical compositions comprising these crystalline forms.

Methods of administering a delayed release 6-mercaptopurine pharmaceutical composition to patients suffering from inflammatory bowel disease which provide for release of the 6-mercaptopurine after passage of the pharmaceutical composition through the stomach are disclosed. The methods result in significant clinical improvement despite leading to very little systemic absorption of 6-mercaptopurine and also result in very few undesirable side effects.

A Sitagliptin phosphate characterized by data selected from the group consisting of: a powder XRD pattern with peaks at 4.7, 13.5, 17.7, 18.3, and 23.7 +-0.2 degrees two theta;a powder XRD pattern with peaks at about 4.7, 13.5, and 15.5 +-0.2 degrees two theta and at least another two peaks selected from the following list: 14.0, 14.4, 18.3, 19.2, 19.5 and 23.7 +-0.2 degrees two theta;and a powder XRD pattern with peaks at about 13.5, 19.2, and 19.5 +-0.2 degrees two theta and at least another t...

A Sitagliptin crystalline form characterized by PXRD pattern having any 5 peaks selected from the group consisting of 7.4, 11.5, 16.7, 17.7, 18.9, 24.1, 24.5, 27.0, 28.5 and 28.8 +- 0.2 degrees 2-theta, wherein any combination of peaks selected includes the peak at 7.4 +- 0.2 degrees two theta, processes for preparing said Sitagliptin crystalline form, and pharmaceutical compositions thereof, are provided.

Intermediate compounds in the synthesis of Sitagliptin, 3-amino-4-(2,4,5- trifluorophenyl)but-2-enoic acid alkyl ester, and amino protected-3-amino-4-(2,4,5- trifluorophenyl)but-2-enoic acid alkyl ester, and the stereoselective reduction of these compound to give Synthon I, or the amino-protected Synthon I, are provided.

The invention provides enzymatic reduction processes for the preparation of 4-(2,4,5- trifluorophenyl)-3-hydroxybutanoate, particularly, (S)-methyl 4-(2,4,5-trifluorophenyl)-3- hydroxybutanoate, a key intermediate in the synthesis of Sitagliptin, and the (S)- and (R)- enantiomers of methyl 4-(2,4,5-trifluorophenyl)-3-hydroxybutanoate in high enantiomeric purity.

Provided are methods for the enantiomeric purification of Linezolid hydroxide, comprising providing a solution or a slurry of Linezolid hydroxide and a solvent selected from alcohols and ketones and crystallizing Linezolid hydroxide from the solution or slurry to obtain Linezolid hydroxide with a low content of S isomer.