Abstract: The present invention relates to a process for the preparation of angiotensin receptor blockers or its pharmaceutically acceptable salts thereof containing less than 10 ppm of the azido impurities.

Abstract: The present invention relates to a process for the preparation of angiotensin receptor blockers or its pharmaceutically acceptable salts thereof containing less than 10 ppm of the azido impurities.

Abstract: The invention relates to a process of preparation of enantiomerically pure Linezolid Form-I comprising converting a substantially enantiomerically pure linezolid hydroxide compound of formula II to Linezolid Form I compound of formula I.

Abstract: The invention relates to a substantially pure linezolid hydroxide having R-isomer content more than about 99.9% relative to its S-isomer. Further aspect of invention provides the ambient moisture condition, which is critical for enantiomeric pure linezolid hydroxide. The obtained substantially enantiomerically pure linezolid hydroxide compound of formula-II can be subsequently converted into the linezolid compound of formula-I, having S-isomer content more than 99.9% relative to R-isomer. Further the invention provides an improved process for preparation of enantiomeric pure linezolid Form-I, wherein linezolid Form-I having the purity more than 99.9% relative to any other known polymorphic form of linezolid. The obtained enantiomeric pure linezolid Form-I can be subsequently converted into the other known polymorphic forms linezolid. The invention also provides stable and substantially solvent-free crystal of Form-I of linezolid.

Abstract: A method is provided for the isolation of high purity crystalline citalopram (1-[3-dimethylamino)propyl}-1-(4-fluorophenyl)-1, 3-dihydro-5-isobenzofurancarbonitrile) base directly from the alkylation reaction mixture of 5-cyanophthalane with N,N-dimethylaminoprpylchloride in a polar aprotic solvent using a strong base. The method comprises: (a) diluting the reaction mixture with ice cold water and extracting the resulting mixture with a water-immiscible organic solvent; (b) re-extracting the water-immiscible organic solvent extract with an aqueous acid; (c) diluting the aqueous acid extract with a substantially equal volume of a water miscible organic solvent, based on the volume of water in the aqueous acid extract; (d) adjusting the pH to basic with an inorganic base to precipitate free crystalline base and (e) further isolating the precipitated free crystalline base by filration.

Abstract: A method is provided for the isolation of high purity crystalline citalopram (1-[3-dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydro-5-isobenzofurancarbonitrile) base directly from the alkylation reaction mixture of 5-cyanophthalane with N,N-dimethylaminopropylchloride in a polar aprotic solvent using a strong base. The method comprises: (a) diluting the reaction mixture with ice cold water and extracting the resulting mixture with a water-immiscible organic solvent; (b) re-extracting the water-immiscible organic solvent extract with an aqueous acid; (c) diluting the aqueous acid extract with a substantially equal volume of a water miscible organic solvent, based on the volume of water in the aqueous acid extract; (d) adjusting the pH to basic with an inorganic base to precipitate free crystalline base, and (e) further isolating the precipitated free crystalline base by filtration.