Desmethyl Chlorpheniramine maleate salt

Desmethyl Chlorpheniramine maleate salt is a demethylated analog of Chlorpheniramine, featuring a piperidine ring linked to a substituted benzene ring via an ethyl chain, with a terminal amine deprotonated as the maleate salt. The compound retains the core antihistaminic scaffold but lacks a methyl group at the N-ethyl position, altering its lipophilicity and metabolic stability. The maleate moiety, a di-carboxylic acid derivative, forms an ionic bond with the amine, enhancing solubility. This impurity arises via N-demethylation during synthesis or degradation pathways. It serves as an HPLC reference standard for quantifying process-related impurities in Chlorpheniramine drug substance.