Determination of kurarinone in rat plasma by UPLC-MS/MS.

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine kurarinone in rat plasma using chlorzoxazone as the internal standard (IS). Sample preparation was accomplished through a liquid-liquid extraction procedure with ethyl acetate to 0.2 mL plasma sample. The analyte and IS were separated on an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with the mobile phase of acetonitrile and 1% formic acid in water with gradient elution at a flow rate of 0.40 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reactions monitoring (MRM) of the transitions at m/z 437.0→301.2 for kurarinone and m/z 168.1→132.1 for IS. The linearity of this method was found to be within the concentration range of 20-2000 ng/mL with a lower limit of quantification of 20 ng/mL. Only 3.0 min was needed for an analytical run. The matrix effect was 94.7-107.2% for kurarinone. The intra- and inter-day precision (RSD%) were less than 8.2% and accuracy (RE%) was within ±9.0%. The recovery ranged from 77.3% to 85.6%. Kurarinone was sufficiently stable under all relevant analytical conditions. The method was also successfully applied to the pharmacokinetic study of kurarinone in rats.