Determination and pharmacokinetic study of echinatin by UPLC-MS/MS in rat plasma

Echinatin, one of the bioactive components of licorice, has exhibited diverse therapeutic effects, including anti-inflammatory and anti-oxidant effects. However, determination and pharmacokinetic study of echinatin in biomatrices have not been conducted. In this study, a simple and fast ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantification of echinatin in rat plasma was developed, fully validated and subsequently well used in a pharmacokinetic research of echinatin after oral and intravenous administration. Rat plasma samples were operated with a simple one-step acetonitrile precipitation, and licochalcone A was used as the internal standard. Chromatographic separation of echinatin was conducted using an UPLC BEN C18 column and a gradient water (containing 0.1% formic acid)-acetonitrile mobile phase. A Waters XEVO TQS-micro Triple-Quadrupole Tandem Mass Spectrometer operating in positive electrospray ionization mode was used for detection. The approach was proved to be linear in the range of 1-1000 ng/mL and well satisfy the requirements from the guidelines of FDA. A pharmacokinetic study of echinatin was carried out by the new developed method following intravenous and oral administration to adult male Sprague-Dawley rats. Echinatin was demonstrated to be quickly absorbed and eliminated and extensively distributed with an absolute bioavailability of approximately 6.81%.