Enantioselective determination of sotalol enantiomers in biological fluids using high-performance liquid chromatography

Abstract

A simple and sensitive high-performance liquid chromatograhic (HPLC) method for the determination of (+)-( S)-sotalol and (−)-( R)-sotalol in biological fluids was established. Following extraction with isopropyl alcohol from biological samples on a Sep-Pak C 18 cartridge, the eluent was derivatized with 2,3,4,6-tetra-O-acetyl-β- d-glucopyranosol isothiocyanate (GITC). The diastereoisomeric derivatives are resolved by HPLC with UV detection at 225 nm. Calibration was linear from 0.022 to 4.41 μg/ml in human plasma and from 0.22 to 88.2 μg/ml in human urine for both (+)-( S)- and (−)-( R)-sotalol. The lower limit of determination was 0.022 μg/ml for plasma and 0.22 μg/ml for urine. The within-day and day-to-day coefficients of variation were less than 7.5% for each enantiomer at 0.09 and 1.8 μg/ml in plasma and at 0.44 and 4.4 μg/ml in urine. The method is also applicable to other biological specimens such as rat, mouse and rabbit plasma.