Chiral evaluation of fluvastatin in human plasma by high-performance liquid chromatography electrospray mass spectrometry

The report describes for the first time the enantioselective analysis of fluvastatin in plasma using LC–MS–MS. The enantiomers of fluvastatin (FV) were extracted from plasma with diisopropyl ether at pH 5.0. The enantiomers were separated on a ChiralCel® OD-R column with a mobile phase consisting of a mixture of acetonitrile, methanol and water (24:36:40) containing 0.1% formic acid. The protonated ions and their respective product ions were monitored in two functions, 410.6 > 348.2 for FV enantiomers and 307.1 > 161.6 for the internal standard (warfarin). Recoveries were higher than 90% and the quantitation limit was 1.5 ng mL−1 plasma for both enantiomers. The coefficients of variation and the relative errors obtained for the validation of the intra- and interassay precision and accuracy were less than 10%. The method was applied to the investigation of the enantioselective pharmacokinetics of FV administered in a single dose of 40 mg (Lescol®, Novartis, São Paulo, SP, Brazil) to a patient with primary hypertension and hypercholesterolemia and genotyped as CYP2C9*1/*1. The data showed higher plasma concentrations of the (−)-3S,5R-fluvastatin enantiomer, with an AUC (−)/(+) of 1.84. Oral clearance values (CL/F) were 29.27 and 49.58 L/h, respectively, for the (−)-3S,5R- and (+)-3R,5S-fluvastatin enantiomers.