Liquid chromatography-tandem mass spectrometry assay for the quantitation of beta-dihydroartemisinin in rat plasma.

Dihydroartemisinin (DHA) is a sesquiterpene used in the world as an antimalarial. To evaluate the pharmacokinetics of dihydroartemisinin in rats, a sensitive and specific liquid chromatography/tandem mass spectrometric (LC-MS/MS) method was developed and validated for the quantitation of dihydroartemisinin in rat plasma. For detection, a Sciex API 4000 LC-MS/MS with a TurboIonSpray ionization (ESI) inlet in the positive ion-multiple reaction monitoring (MRM) mode was used. The plasma samples were pre-treated by a simple liquid-liquid extraction with diethyl ether. The statistical evaluation for this method reveals excellent linearity, accuracy and precision for the range of concentrations 0.2-100.0 ng/mL. The method had a lower limit of quantification (LLOQ) of 0.2 ng/mL for beta-dihydroartemisinin in 100 microL of plasma. The method was successfully applied to the characterization of the pharmacokinetic profile of beta-dihydroartemisinin in rats after oral administration.