Olsalazine sodium Impurity H

Olsalazine sodium Impurity H is a structurally related degradation byproduct derived from the azo-linked dimeric scaffold of olsalazine, featuring a sodium salt of a 5-aminosalicylic acid derivative with altered intermolecular linkage. Its core structure retains the aromatic hydroxyl and carboxylic acid functionalities but exhibits a distinct isomeric configuration at the azo coupling site, resulting in reduced dimer stability. This impurity arises via non-enzymatic hydrolysis under alkaline conditions, reflecting a specific pathway of API breakdown. It serves as a critical HPLC reference standard for quantifying degradation products in olsalazine formulations.