Determination of GL-V9, a derivative of wogonin, in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study after oral and pulmonary administration.

GL-V9, a derivative of wogonin, shows much more potent anticancer properties than wogonin. In this study, a selective, sensitive and rapid ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of GL-V9 in rat plasma. Plasma samples were processed using methanol to precipitate protein. Chromatographic separation of analytes was achieved on a C18 column using gradient elution within 4.5 min. The mobile phase consisted of acetonitrile and water including 0.1% (v/v) formic acid and 5 mm ammonium acetate. GL-V9 and caffeine (internal standard) were monitored by positive electrospray triple quadrupole mass spectrometer and quantified using multiple reaction monitoring (MRM) mode with the transitions of m/z 410.20 → 126.10 (GL-V9) and 195.10 → 138.00 (IS: caffeine), respectively. Good linearity was obtained over the range of 2-1000 ng/mL (R2  > 0.99) and the extraction recovery was 101.91 ± 11.34%. The intra- and inter-day precision variations were small (RSD 1.35-6.96%) and the relative error (RE) of accuracy was -7.35-6.27%. The established and validated UPLC-MS/MS method was successfully applied to study the pharmacokinetic behavior of GL-V9 after administration through different delivery routes. The results demonstrated that pulmonary delivery exhibited a greater advantage in terms of improving bioavailability compared with oral administration.