Atenolol EP Impurity H

Atenolol EP Impurity H is a degradation byproduct arising from oxidative cleavage of the parent drug's hydroxyl group, resulting in a ketone functionality at the 4-position of the benzene ring. Retaining the methoxy and cyclopropylsulfonamide moieties, this impurity exhibits a conjugated aromatic system and a zwitterionic character due to the sulfonamide group. Its structural divergence from Atenolol is critical for identifying oxidative degradation pathways in stability studies. This compound serves as an HPLC reference standard for quantifying oxidative impurities in Atenolol formulations.