Pheniramine N-oxide Dihydrochloride

Pheniramine N-oxide Dihydrochloride is a degradation byproduct of the antihistamine Pheniramine, featuring an N-oxidized tertiary amine and a dihydrochloride salt form. The compound retains the core 1-phenyl-4-(4-piperidinyl)butan-1-one scaffold of the parent drug, with oxidation at the piperidine nitrogen and protonation as the dihydrochloride derivative. This impurity arises under oxidative stress conditions, exhibiting altered physicochemical properties due to the N-oxide functionality. It serves as a critical HPLC reference standard for quantifying oxidative degradation pathways in Pheniramine-based formulations.