| abstract |
A process for the preparation of atorvastatin calcium in amorphous form is disclosed. The process comprises (i) treating diol protected tertbutyl ester with a methanolic solution in the presence of an aqueous acid; (ii) adding aqueous hydroxide solution to the reaction mixture; and removing unreacted diol protected tert-butyl ester (a) by solvent extraction (iii) treating the product obtained in step (ii) with calcium chloride solution to obtain crude amorphous atorvastatin calcium salt; (iv) isolating said crude salt; (v) treating the crude salt with excess volume of methanol; (vi) treating the product of step (v) with activated carbon and (vii) precipitation of the product by adding methanolic solution of atorvastatin calcium in to water (viii) recovering the pure product by filtration and drying. |