Patent ID: 6846932

Claim:
A process for the preparation of pharmaceutically acceptable chiral salts of Amlodipine namely S(−) Amlodipine salts having formula (1) and R(+) Amlodipine salts having formula (2) wherein R is selected from the group consisting of benzenesulphoinic acid, succinic acid, malic acid, oxalic acid and p-toluenesulphonicacid, wherein the salts of formula 1 and 2 are prepared without isolation of a free base with optical purity ranging between 96-99% the process comprising: (a) reacting a solution of RS amlodipine base in an organic solvent with a solution of L(+) or D(−) tartaric acid in an organic solvent at temperature ranging from 20-35° C. for a period ranging between 16-24 hrs., to obtain a solvate comprising an amlodipine tartarate salt; (b) separating and reacting the amlodipine tartarate salt obtained in step (a) with an aqueous solution of an acid optionally in presence of an organic solvent, and at a temperature ranging between 20-40° C.; (c) adding water to the reaction mixture of step (b) to obtain the salt of formula 1 and 2, separating the salt of formula 1 and 2 and drying to obtain salt corresponding to the acid used in step (2) with co ranging from 96-99%.