Pharmacokinetic and excretion study of three secoiridoid glycosides and three flavonoid glycosides in rat by LC–MS/MS after oral administration of the Swertia pseudochinensis extract

A sensitive, specific and rapid liquid chromatography–mass spectrometry (LC–MS/MS) method has been developed and validated for the simultaneous determination of swertiamarin, gentiopicroside, sweroside, mangiferin, isoorientin and isovitexin in rat plasma, bile, urine and feces after oral administration of Swertia pseudochinensis extract using sulfamethalazole (SMZ) as an internal standard (IS). The samples were pretreated and extracted by liquid-liquid extraction as the sample clean-up procedure. The chromatographic separation was performed on a C18 column with a linear gradient elution using a mobile phase consisted of 0.1% formic acid and methanol at a flow rate of 0.8 mL/min. The total run time was 10 min. Determination and quantification of the analytes were achieved by use of a hybrid quadrupole linear ion-trap mass spectrometer. A multiple-reaction monitoring scanning (MRM) method with electrospray ionization (ESI) source was employed with simultaneously monitoring the positive and negative electrospray ion source polarity in a single run. A full validation of the method was performed. The linearity of the analytical response was good, with correlation coefficients greater than 0.9953. The intra-day and inter-day precisions (RSD %) exhibited within 10.4%, and the accuracy (RE %) ranged from −8.7% to 9.5%. A non-compartmental model was employed to calculate the parameters. The values of elimination rate constants (Ke) ranged from 0.0026 to 0.0118 and the elimination half-life (T1/2) ranged from 58.4 to 263.0 min. This is the first report on pharmacokinetic and excretion study of Swertia pseudochinensis extract after oral administration. The results provided a meaningful basis for the clinical application of this herb.