Diclofenac EP Impurity D

Diclofenac EP Impurity D is a sodium salt of a 4-bromo-2-chloroaniline-derived benzoyl acid, featuring a substituted aromatic ring with bromine and chlorine atoms at para and ortho positions relative to the carboxylic acid moiety. Its structure incorporates a heterocyclic amide linkage analogous to the parent diclofenac molecule but with halogen substitution differences. This impurity arises from synthetic pathway deviations involving brominated intermediates. It serves as an HPLC reference standard for quantifying process-related impurities in diclofenac formulations.