Determination of schizandrin in rat plasma by high-performance liquid chromatography–mass spectrometry and its application in rat pharmacokinetic studies

A sensitive liquid chromatography–mass spectrometric (LC/MS) method for the quantification of schizandrin in rat plasma was developed and validated after solid-phase extraction (SPE). Chromatographic separation was achieved on a reversed-phase Shimadzu C18 column with the mobile phase of acetonitrile–sodium acetate (10 μmol/L) and step gradient elution resulted in a total run time of about 11.7 min. The analytes were detected using an electrospray positive ionization mass spectrometry in the selected ion monitoring (SIM) mode. A good linear relationship was obtained in the concentration range studied (0.005–2.000 μg/mL) (r = 0.9999). Lower limit of quantification (LLOQ) was 5 ng/mL and the lower limit of detection (LLOD) was 2 ng/mL using 100 μL plasma sample. Average recoveries ranged from 75.85 to 88.51% in plasma at the concentrations of 0.005, 0.100 and 1.000 μg/mL. Intra- and inter-day relative standard deviations were 5.95–12.93% and 3.87–14.53%, respectively. This method was successfully applied for the pharmacokinetic studies in rats.