Diclofenac EP Impurity C

Diclofenac EP Impurity C is a chlorinated aromatic derivative structurally related to diclofenac, featuring a substituted benzene ring with two chlorine atoms and an aniline moiety. Its core structure retains the 2-aminophenylpropanoid scaffold but lacks the carboxylic acid group present in the parent drug, instead bearing a hydroxylated or partially oxidized side chain. This impurity arises from oxidative degradation pathways during synthesis or storage, forming a stable, low-molecular-weight byproduct. It serves as a critical HPLC reference standard for quantifying process-related impurities in diclofenac formulations.