Development and validation of liquid chromatography–tandem mass spectrometry method for simultaneous determination of four tertiary alkaloids in rat plasma and its application to a pharmacokinetic study

Abstract

A specific and reliable liquid chromatography–electrospray ionization-tandem mass spectrometry method was developed for the simultaneous determination of tetrahydropalmatine (THP), tetrahydroberineper (THB), tetrahydrocoptisine (THC) and corydaline (CDL) in rat plasma using jatrorrhizine as internal standard. Plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a Zorbax Eclipse Plus C18 column (3.0mm×100mm, 1.8μm) with gradient elution using acetonitrile–0.1% formic acid water as mobile phase at a flow rate of 0.3mL/min. The detection was carried out by a triple–quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The mass transition ion-pair was followed as m/z 356.2→192.1, m/z 324.1→176.0, m/z 340.1→176.0, and m/z 370.3→192.1 for THP, THC, THB and CDL. Linear calibration curves were obtained over the range of 0.2–2000ng/mL, and the method limits were 2.0ng/mL for THC, 0.2ng/mL for THB, 1.0ng/mL for THP, and 0.4ng/mL for CDL, respectively. The mean recovery of the analytes ranged from 85.51% to 93.99%. The intra- and inter-day precisions were in the range of 1.21–4.73% and the accuracies were between 92.23% and 98.23%. The validated method was successfully applied to a pharmacokinetic study of THP, THB, THC and CDL in rat plasma following oral administration of Jitai tablet.