Orlistat USP Related Compound D is a synthetic byproduct arising from partial hydrolysis of the parent drug, characterized by a tetrahydrofuran ring linked to a chlorophenyl moiety and a terminal carboxylic acid group. This impurity retains the core scaffold of Orlistat but features an ester-to-acid transformation at the ฮฒ-lactone site, disrupting its lipase-inhibitory activity. Structurally, it exhibits a branched alkyl chain with a primary amide functionality, essential for its role as an HPLC reference standard in impurity profiling of Orlistat-based pharmaceuticals.
