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 UPLC (TM) BEH C-18 column (50 mm x 2.1 mm, i.d., 1.7 mu m) with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.25 mL min(-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 10-2500 ng mL(-1) with lower limit of quantification (LLOQ) of 10 ng mL(-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 +/- 12.6%. The developed method was applied for the first time to the pharmacokinetic study of VOR in rats following a sin.-le oral dose. (C) 2007 Elsevier B.V. All rights reserved.