(S)-Phenylephrine Hydrochloride

(S)-Phenylephrine Hydrochloride is the enantiomerically pure S-isomer of phenylephrine hydrochloride, characterized by a chiral center at the α-carbon adjacent to the benzene ring. Its structure comprises a substituted benzene ring with a 3,4-dihydroxyphenethyl backbone, forming a zwitterionic hydrochloride salt. The compound retains the core pharmacophore of the parent drug, phenylephrine, but exhibits distinct stereochemical properties influencing its biological activity. As an API impurity, it arises during enantioselective synthesis or racemic resolution processes. This compound serves as a critical HPLC reference standard for enantiomeric purity analysis in phenylephrine formulations.