Cefpodoxime Proxetil impurity G (Crude) is a cephalosporin-derived impurity arising from the synthetic pathway of the parent API, characterized by a 7-aminocephalosporanic acid core substituted with a 2-amino-4-methyl-5-oxazolyl side chain and a proxetil ester group. The compound retains the ฮฒ-lactam and thiazole moieties but exhibits a truncated oxime functionality at the C-3 position, distinguishing it from the active drug. This structural deviation results from a side reaction during esterification, leading to partial cleavage of the oxime linkage. It serves as a critical HPLC reference standard for quantifying process-related impurities in cefpodoxime formulations.
