Validated UPLC-MS/MS method for determination of hordenine in rat plasma and its application to pharmacokinetic study.

Hordenine is an active compound found in several foods, herbs and beer. In this work, a sensitive and selective UPLC-MS/MS method for determination of hordenine in rat plasma was developed. After addition of caulophylline as internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used as sample preparation. Chromatographic separation was achieved on a UPLC BEH HILIC (2.1 mm × 100 mm, 1.7 μm) with acetonitrile (containing 10mM ammonium formate) and water (containing 0.1% formic acid and 10 mM ammonium formate) as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used for quantification using target fragment ions m/z 166.1 → 121.0 for hordenine and m/z 205.1 → 58.0 for IS. Calibration plots were linear over the range of 2-2000 ng/mL for hordenine in rat plasma. Mean recoveries of hordenine in rat plasma were in the range of 80.4-87.3%. RSD of intra-day and inter-day precision were both <8%. The accuracy of the method ranged from 97.0% to 107.7%. The method was successfully applied to pharmacokinetic study of hordenine after oral and intravenous administration.