15-EPI BIMATOPROST

15-EPI Bimatoprost is a stereochemically distinct epimer of the parent drug, featuring inversion of configuration at the 15β-hydroxyl position. This structural modification preserves the core cyclopentylprostaglandin scaffold but alters the spatial orientation of the lateral chain hydroxyl group, resulting in distinct chromatographic behavior while maintaining similar molecular interactions. The compound arises as a synthetic byproduct during API manufacturing processes involving asymmetric synthesis of the 15α-hydroxyl stereocenter. Functions as a critical HPLC reference standard for quantifying epimeric impurity levels in bimatoprost formulations.