Pharmacokinetics of Oxymatrine in Rat After Intravenous Administration by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

Oxymatrine is an alkaloid active ingredient extracted from the traditional Chinese medicinal plant Sophora flavescens Ait. It has anti-inflammatory, anti-fibrosis and cirrhosis, anti-arrhythmia, and anti-tumor effects. In this study, we used UPLC-MS/MS to detect oxymatrine in rat plasma, and investigated its pharmacokinetics in rats. Six rats were given oxymatrine (2 mg/kg) by intravenous (iv) administration. The blood (100 mu L) was withdrawn from the caudal vein at 5, 30 min, 1, 2, 4, 6, 8, 12, and 24 h after administration. Chromatographic separation was achieved using a UPLC BEH C18 column using mobile phase of acetonitrile-0.1 % formic acid with gradient elution. Electrospray ionization (ESI) tandem mass spectrometry in multiple reactions monitoring (MRM) mode with positive ionization was applied. Intra-day and inter-day precision RSD of oxymatrine in rat plasma were lower than 13%. The method was successfully applied in the pharmacokinetics of oxymatrine in rats after intravenous administration. The t1/2 of oxymatrine is 4.9 +/- 3.4 h, which indicates the quick elimination.