Determination of Sophorabioside in Rat Plasma by UPLC-MS/MS and its Application to a Pharmacokinetic Study

A ultra-performance liquid chromatography tandem mass spectrometry method was initially developed and validated for quantification of sophorabioside in rat plasma using kaempferol-3-O-β-D-rutinoside as the internal standard (IS). Analyte and IS were preparation through a protein precipitation procedure with 1.0 mL of methanol to a 0.1 mL plasma sample. The processed samples were separated by C18 analytical column using methanol/water containing 0.1% formic acid with gradient elution as the mobile phase at a flow rate of 0.3 mL/min. Sophorabioside (m/z 577.15 → 269.45) and kaempferol-3-O-β-D-rutinoside (m/z 593.15 → 285.84) were detected by a triple quadrupole tandem mass spectrometer in negative electrospray ionization mode using multiple reaction monitoring. The calibration curve for sophorabioside was linear in the range of 6-1,200 ng/mL (r2 > 0.995) with a lower limit of quantification of 6 ng/mL. The inter- and intra-day precision and accuracy were well within the acceptable limits. The matrix effects were satisfactory in all of the biological matrices examined. The mean recovery of sophorabioside was always >90%. This method was successfully applied to a pharmacokinetic study of sophorabioside in rats after an oral administration of 90 mg/kg sophorabioside. The main pharmacokinetic parameters: Tmax, Cmax and t1/2 were 6.2 ± 0.8 h, 1430.83 ± 183.25 ng/mL, 7.2 ± 0.5 h, respectively.