Simultaneous determination and pharmacokinetics of fourteen bioactive compounds in rat plasma by LC-ESI-MS/MS following intravenous injection of Gegen-Sanqi compatibility solution.

A high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed and fully validated for simultaneous determination of puerarin, 3'-hydroxy puerarin, 6″-O-xylosyl puerarin, 3'-methoxy puerarin, mirificin, puerarin-7-O-glucoside, daidzin, daidzein, daidzein-7-O-glucoside, ginsenoside-Rd, notoginsenoside-R1, ginsenoside-Re, ginsenoside-Rg1, ginsenoside-Rb1 in rat plasma after intravenous injection of 5mL/kg Gegen-Sanqi compatibility solution (containing Pueraria flavonid 10.8mg/mL and Panax notoginsenosidum 5.4mg/mL). After addition of internal standard (IS) baicalin, the analytes and IS were recovered from rat plasma by protein precipitation using acetonitrile containing 0.1% formic acid. Chromatographic separation was performed on a Capcell pak MG C18 column (3.0mm×75mm, 3.0μm) at 35°C with a flow rate of 0.75mL/min. Mass spectrometry was conducted using multiple reaction monitoring in positive mode. The method was linear for all of the analytes over 1000 times concentration range with correlation coefficients greater than 0.99. The precision and accuracy of the LC-MS/MS assay based on the three analytical quality control (QC) levels were well within the acceptance criteria from FDA guidance for bioanalytical method validation. Method recoveries were higher than 75% and the matrix effects were minimal. All analytes were stable under tested conditions. It was the first time to study the pharmacokinetics of daidzein-7-O-glucoside in rat plasma. To the best of our knowledge, this is the first study for simultaneous determination of so many analytes in rat plasma after intravenous injection of Gegen-Sanqi compatibility solution. It was expected that the present work would provide some helpful references for the apprehension of the mechanism of action and further clinical efficacy studies of Gegen-Sanqi herb-pair.