Deflazacort-21-formate

Deflazacort-21-formate is a 21-hydroxy ester derivative of deflazacort, featuring a formate moiety at the C-21 position. This structural modification introduces a formyl oxygen linkage, altering the parent corticosteroid's solubility and metabolic stability. The compound retains the 16α-methylated pregnane core with a 17α-carboxylic acid group, characteristic of deflazacort’s anti-inflammatory profile. It arises as a specific degradation byproduct under acidic conditions, reflecting ester hydrolysis sensitivity. This impurity serves as a critical HPLC reference standard for quantifying degradation pathways in deflazacort formulations.