Rosuvastatin S-Isomer

Rosuvastatin S-Isomer is the enantiomerically pure S-configured stereoisomer of Rosuvastatin, differing in the absolute configuration at the chiral sulfoxide center. It retains the core structure comprising a pyridine-fused dihydropyridine ring, a fluorinated cyclopropylmethyl substituent, and a calcium-coordinated sulfone moiety. This impurity arises from partial stereoselective synthesis during API manufacturing, resulting in residual S-enantiomer enrichment. It serves as an HPLC reference standard for enantiomeric purity profiling in quality control.