azelnidipine Ethyl imp

Azelnidipine Ethyl imp is a dihydropyridine-based calcium channel blocker impurity, featuring an ethyl ester substitution at the 3-position of the pyridine ring, alongside a nitrophenyl group and a dimethylaminoethyl side chain. This compound arises as a synthetic byproduct during the esterification step of azelnidipine production, retaining the core 1,4-dihydropyridine scaffold but with an ethyl moiety replacing a methylene bridge. Its structural similarity to the parent drug enables competitive binding in analytical assays, serving as a critical HPLC reference standard for quantifying process-related impurities in azelnidipine APIs.