Atorvastatin calcium trihydrate Impurity:7-(4-Fluorophenyl)hexahydro-ß,7-dihydroxy-1b-(1-methylethyl)-7a-phenyl-1a-[(phenylamino)carbonyl]-3H-oxireno[3,4]pyrrolo[2,1-b][1,3]oxazine-3-butanoic Acid Sodium Salt( Atorvastatin calcium-cycloIP Sodium Salt.