Chlorhexidine Dihydrochloride Impurity B

Chlorhexidine Dihydrochloride Impurity B is a truncated biguanide derivative characterized by a bis-guanidinium core linked via a hexamethylene bridge, substituted with a 4-chlorophenyl group and a hydroxylated aliphatic side chain. Its structure lacks one aromatic ring relative to the parent Chlorhexidine, resulting in reduced conjugation and altered charge distribution. The compound exists as a dihydrochloride salt, featuring two chloride counterions. This impurity arises from partial oxidation of the aliphatic chain during synthesis, introducing a hydroxyl functionality. It serves as an HPLC reference standard for quantifying process-related impurities in Chlorhexidine formulations.