50-Carboxycyanocobalamin (Crude) is a cobamide derivative featuring a corrin ring system with a central cobalt ion coordinated to a cyanide ligand and a 5'-deoxyadenosyl moiety. It contains an additional carboxylate group at the 50-position, introducing a negatively charged functional group that alters the molecule's hydrophilicity and coordination geometry compared to Cyanocobalamin. This impurity arises via oxidative degradation pathways, specifically hydroxylation followed by carboxylation of the lower axial position. It serves as an HPLC reference standard for quantifying process-related impurities in Cyanocobalamin formulations.
