Determination of vitexin-2''-O-rhamnoside in rat plasma by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry and its application to pharmacokinetic study.

A rapid, sensitive and selective ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed for the determination and pharmacokinetic study of vitexin-2''-O-rhamnoside (VOR) in rat plasma. The method involved a simple protein precipitation with methanol. The separation was performed on an ACQUITY UPLCtrade mark BEH C(18) column (50mmx2.1mm, i.d., 1.7mum) with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.25mLmin(-1). Electrospray ionization (ESI) in positive ion mode and multiple reaction monitoring (MRM) was used for the quantification of VOR with a monitored transitions m/z 579-->433 for VOR and m/z 611-->303 for internal standard (I.S., hesperidin). Linear calibration curves were obtained over the concentration range of 10-2500ngmL(-1) with lower limit of quantification (LLOQ) of 10ngmL(-1). The intra- and inter-day precisions (R.S.D. %) were less than 11% and 2.4%, and accuracy (RE %) between -9.3% and 1.0% (n=5). The average extraction recovery of VOR was 97.2+/-2.6%. The developed method was applied for the first time to the pharmacokinetic study of VOR in rats following a single oral dose.