Darifenacin-N-oxide

Darifenacin-N-oxide is an oxidation derivative of the anticholinergic drug Darifenacin, featuring an N-oxide group at the quinuclidine nitrogen. This modification introduces a polar, electron-withdrawing oxygen atom, altering the compound's lipophilicity and metabolic stability. Structurally, it retains the 8-chloro-2-methylquinuclidine core and 4-(dimethylamino)-3-methoxybenzoyl moiety of the parent molecule, with the N-oxide substituting a tertiary amine hydrogen. The compound serves as a critical impurity reference standard for HPLC-based quantification of oxidation-related degradation pathways in Darifenacin formulations.