倍他司汀杂质4（盐酸盐）

Betahistine Impurity 4 (CAS 88796-99-0), chemically betahistine N-oxide, is an oxidative degradation product of betahistine in which the pyridine nitrogen of the parent molecule is converted to the N-oxide form (N-methyl-2-(pyridin-2-yl)ethanamine N-oxide; C8H12N2O, MW 152.19). As a betahistine-related substance, it is used as a reference standard for the identification and quantification of this impurity in betahistine APIs and finished formulations, supporting HPLC method validation, stability studies, and regulatory impurity profiling.