Patent ID: 7456297

Claim:
A process for preparing atorvastatin hemi-calcium Form V, having a charasteric of X-ray diffractogram has two medium peaks at 5.3±0.2 and 8.3±0.2 degrees 2θ and one large peak in the range 18-23 degrees 2θ with a maximum at about 18.3±0.2 degrees two-theta, comprising the steps of: a) suspending [R-(R*,R*)]-2-(4-fluorophenyl)- β,δ-dioxane-5-(1-methylethyl)-3-phenyl-4-[(phenylamino)carbonyl]-1H-pyrrole-1-tert-butylheptanoic acid ester in ethanol, b) deprotecting the [R-(R*,R*)]-2-(4-fluorophenyl)-β, δ-dioxane-5-(1-methylethyl)-3-phenyl-4-[(phenylamino)carbonyl]-1H-pyrrole-1-tert-butylheptanoic ester by adding hydrochloric acid to the suspension, thereby forming a solution of atorvastatin lactone and [R-(R*,R*)]-2-(4-fluorophenyl)-β, δ-dihydroxy-5-(1-methylethyl)-3-phenyl-4-[(phenylamino)carbonyl]-1H-pyrrole-1-tert-butylheptanoic acid ester in ethanol, c) adding calcium hydroxide to the solution, thereby forming a solution of atorvastatin hemi-calcium in ethanol, d) precipitating atorvastatin hemi-calcium from the solution, and e) drying the precipitated atorvastatin hemi-calcium to obtain atorvastatin hemi-calcium as Form V.