Determination of Rubiadin in Mouse Blood by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry and its Application to Pharmacokinetics

Rubiadin exists in various plants, such as Lepironia, Quassia, Amaranthaceae, etc. Its resources are plentiful, it has no estrogenic side effects as a bone resorption inhibitor, and it possesses antituberculous, antifungal, and anticarcinogenic activities, thus showing a good prospect for application. A rapid and simple UPLC-MS/MS method was developed to determine rubiadin in mouse blood and its application to a pharmacokinetic study. Licochalcone A (internal standard, IS) and rubiadin were gradient eluted by mobile phase of acetonitrile and water (0.1% formic acid) in a Waters UPLC BEH C18 column. The multiple reaction monitoring of m/z 253.1 -> 224.8 for rubiadin and m/z 337.2 -> 119.7 for IS with an electrospray ionization (ESI) source was used for quantitative detection. The calibration curve ranged from 5 to 5000 ng/mL (r > 0.995). The matrix effects ranged from 87.1% to 92.6%, and the recovery was higher than 83.1%. The precision was less than 13%, and the accuracy ranged from 91.3% to 109.7%. The developed UPLC-MS/MS method was successfully used for a pharmacokinetic study of rubiadin in mice after oral (20 mg/kg) and intravenous administration (5 mg/kg), and the absolute availability of rubiadin was 22.2%.