Atorvastatin EP Impurity E 

Chemical Name: (3S,5S)-7-[2-(4-fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-(propan-2-yl)-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid (as per EP); (3S,5S)-7-[2-(4-fluorophenyl)-5-isopropyl-3-phenyl-4-(phenylcarbamoyl)-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid (as per USP)

Synonym: Ent-Atorvastatin (EP) ; Atorvastatin USP Related Compound E ; Atorvastatin (3S,5S)-enantiomer