Determination of Raddeanin A in rat plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study.

A simple, rapid and sensitive LC-MS/MS analysis method was developed and validated for the determination of Raddeanin A (RA) in rat plasma. Protein precipitation with three volumes of methanol as the precipitation reagent was used as the sample preparation method. The analysis process was performed on a Thermo Syncronis C18 column with the mobile phase of methanol-water (containing 5mM ammonium formate, pH 2.2) (85:15, v/v). RA and glycyrrhetinic acid (internal standard) were monitored under negative electrospray ionization in multiple reaction monitoring (MRM) mode. Retention time of RA and IS were 2.1 min and 3.5 min, respectively. The limit of detection was 5 ng/mL and the linear range was 50-50,000 ng/mL. The intra-day and inter-day precision was 1.87-2.94% and 3.25-5.36%, and the intra-day and inter-day accuracy ranged from 5.9% to 10.5% and 5.6% to 11.1%, respectively. The absolute recovery was above 90.3%. The method has been successfully translated to the pharmacokinetic study of RA in rats after intravenous and intraperitoneal administration (0.75 mg/kg).