Betamethasone 17-Propionate

Betamethasone 17-propionate is a fluorinated corticosteroid derivative featuring a propionyl ester substitution at the C-17 hydroxyl position of the parent betamethasone nucleus. The compound retains the characteristic 16α-methyl, 11β,17α,21-trihydroxy-pregna-1,4-diene core with a 9-fluoro substitution, while the 17β-hydroxyl group is esterified with a propanoyl moiety. This structural modification reduces its inherent reactivity compared to the parent drug, positioning it as a stable synthetic intermediate or degradation byproduct. It serves as a reference standard for HPLC quantification of 17-ester-related impurities in betamethasone formulations.