Simultaneous determination of five active alkaloids from Compound Kushen Injection in rat plasma by LC–MS/MS and its application to a comparative pharmacokinetic study in normal and NSCLC nude rats

Non-small cell lung cancer (NSCLC), as the most common histological type of lung cancer with high mortality rates, has been widely treated by Compound Kushen Injection (CKI) in China. Among various active components with many pharmacologic properties, matrine, oxymatrine, sophoridine, oxysophocarpine and N -methylcytisine, are the main bioactive alkaloids of CKI. Therefore, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously quantify the five alkaloids in nude rat plasma in this study. With aminopyrine as internal standard (IS), plasma samples were extracted by alkalified chloroform and then separated on an Agela Venusil MP C18 column (2.1 mm × 100 mm, 3 μm) using gradient elution. Water containing 10 mmol/L ammonium acetate (adjusted to pH 8.0 with ammonia water, A) and methanol (B) constituted the mobile phase system. Notably, the analysis was rapid and accurate due to a short running time of 6 min and a stereoisomer separation between matrine and sophoridine. Detection was implemented in MRM mode with an electrospray positive ionization source. Validation parameters were all in accordance with current criterion. The established method has been effectively employed to compare the pharmacokinetic behaviors of five alkaloids between normal and NSCLC nude rats. Results indicated that the pharmacokinetic behaviors of oxymatrine, sophoridine and N -methylcytisine from CKI could be changed when it was intravenously administrated to the NSCLC model rats, and possible reasons have been proposed. This study could provide meaningful reference for further clinical medication of CKI when combined with time-effect curve and clinical symptoms. • Simultaneous quantitation of five active compounds of CKI in nude rat plasma • An achievement of stereoisomer separation between matrine and sophoridine • Pharmacokinetic comparison between normal and NSCLC model groups after intravenous administration • Pharmacokinetic behaviors of oxymatrine, sophoridine and N -methylcytisine from CKI could be changed in NSCLC model rats.