abstract |
The present invention provides an improved process for the preparation of Atorvastatin of formula (I) or its salts, preferably hemicalcium salt with purity greater than 99.5% using novel salts of Atorvastatin such as N,N- dicyclohexylethylenediamine salt of Atorvastatin and novel polymorph of Atorvastatin sodium salt. Formula (I). |