Stereoselective analysis of carvedilol in human plasma using HPLC/MS/MS after chiral derivatization

A relatively high-throughput high-performance liquid chromatography/tandem mass spectrometry (HPLC–MS/MS) method using a chiral derivatization reagent was developed for the quantitative determination of carvedilol enantiomers in human plasma. S-carvedilol and R-carvedilol are extracted from human plasma by protein precipitation using acetonitrile containing racemic [ 2H 5]-carvedilol as an internal standard. Extracts are then derivatized with 2,3,4,6-tetra- O-acetyl-beta-glucopyranosyl isothiocyanate (GITC) and analysed using HPLC–MS/MS with a TurboIonspray (TIS) interface and selected reaction monitoring. Using 150 μL of plasma, the method was validated over a concentration range of 0.2–200 ng/mL. The maximum within-run precision observed in a three run quality control was 8.2% for S-carvedilol and 6.7% for R-carvedilol, respectively. The maximum percentage bias observed at all quality control sample concentrations was 9.4% for S-carvedilol and 11.6% for R-carvedilol, respectively. The HPLC–MS/MS method was also compared with a previously developed high-performance LC/fluorescence method by analysing 25 samples containing racemic carvedilol. Based on results obtained, these two methods were found to be equivalent. However, compared with LC/fluorescence method, HPLC–MS/MS method is more sensitive, uses less plasma, and also employs a less time-consuming sample preparation process.