Lupin, Inc.

Vilas Nathu Dhake

Girij Pal Singh

Umesh Babanrao Rananaware

Himanshu Madhav Godbole

Sagar Purushottam Nehate

Suhas Ganpat Tambe

Govind Singh Rawat

Sagar Purshottam Nehate

The present invention relates to a novel method for obtaining (2S,3aS,6aS)-1-[(S)-2-[[(S)-1-(ethoxycarbonyl)-3-phenylpropyl]-amino]propanoyl]octahydro cyclopenta[b]pyrrole-2-carboxylic acid, viz. Ramipril(I) in high optical purity, free of other stereoisomers, and in high bulk density. The present invention also relates to a novel hydrated form of Ramipril(I) and a process for preparation thereof.

Process for crystallization of Ramipril and preparation of a hydrated form thereof

A dicyclohexyamine salt of compound of formula I, namely perindopril, having an X-ray powder diffraction pattern with characteristic peaks (2&#x3b8;): 8.462, 10.624, 18.693, 9.424, 17.272, 14.177, 19.499, 20.765, 21.409, and 14.540.  A process for preparation of the said salt of perindopril and its use in the purification of an impure perindopril and a process for purification of perindropril comprising formation of its salt with dicyclohexylamine. The present invention also relates to preparation of Perindopril tert-butyl amine salt directly from Perindopril dicyclohexylamine salt without isolating the free base.

Process for the purification of perindopril

A novel crystalline form of quinapril hydrochloride of formula (I)  An amorphous form of quinapril hydrochloride substantially free of impurities, specially diketopiperazine compound, and conforming to pharmacopoeial specifications formed from the said novel crystalline form of quinapril hydrochloride of formula (I). The crystalline quinapril hydrochloride is in the form nitroalkane solvate in which the nitroalkane is nitromethane, nitroethane and nitropropanae. Each such nitroalkane solvate having particular characteristic X-ray diffraction patterns. A process for preparation of amorphous form of quinapril hydrochloride, substantially free of impurities, specially diketopiperazine compound, and conforming to pharmacopoeial specifications, using the novel crystalline quinapril hydrochloride as an intermediate. The process involves obtaining free base compound of formula (V) by adjusting the pH of a solution of the benzyl ester maleate salt of quinapril of formula (V) between 7.5-8.5 in a mixture of water and an organic solvent; catalytic hydrogenation of this compound (V) in an alcoholic solvent in the presence of concentrated hydrochloric acid or hydrogen chloride dissolved in an alcoholic solvent and in the presence of catalytic amounts of Pd/C to obtain a residue containing formula (I); crystallization of the said residue by evaporating the alcoholic solvent from a nitroalkane solvent to give crystalline quinapril hydrochloride, associated with a solvate of the nitroalkane solvent, and drying the crystalline quinapril hydrochloride nitroalkane solvate at a temperature between 40&#xb0; C. and 45&#xb0; C. under vacuum to give amorphous quinapril hydrochloride of formula (I).

Crystalline form for quinapril hydrochloride and process for preparing the same

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Pune, India

Vilas Nathu Dhake