orlistat open ring amide impurity

Orlistat open ring amide impurity is a synthetic byproduct formed via hydrolytic cleavage of the tetrahydrotetralin lactone ring in orlistat, resulting in an open-chain amide structure. The compound retains the fluorinated phenyl ring and terminal carboxylic acid ester but features a linearized amide linkage between the cyclohexane and aromatic moieties. This structural modification introduces a free amide NH group, altering its polarity and chromatographic retention compared to the parent API. It serves as a critical HPLC reference standard for monitoring ring-opening degradation pathways in orlistat manufacturing processes.