Atorvastatin EP Impurity K Catalogue A325311 CAS 345891-62-5 M.W 572.67 M.F C34H37FN2O5 Specifications FAQs (3R,5R)-7-[3-(Phenylcarbamoyl)-5-(4-fluorophenyl)-2-isopropyl-4-phenyl-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid methyl ester ;