Amlodipine EP Impurity F

Amlodipine EP Impurity F is a structurally related dihydropyridine derivative featuring an ortho-hydroxy substitution on the phenyl ring and a truncated ester moiety compared to the parent amlodipine. This impurity arises from oxidative cleavage of the methoxy group, introducing a hydroxyl functionality and altering the pharmacophore's electronic properties. Its core scaffold retains the 1,4-dihydropyridine ring and calcium-binding carboxylate, but lacks the methyl ester side chain, rendering it pharmacologically inert. This compound serves as a critical HPLC reference standard for quantifying process-related impurities in amlodipine bulk drug manufacturing.