Simultaneous determination of eight flavonoids in plasma using LC-MS/MS and application to a pharmacokinetic study after oral administration of Pollen Typhae extract to rats.

A sensitive, reliable and validated LC-MS/MS method was developed to determine the presence of eight flavonoids (catechin, typhaneoside, isorhamnetin-3-O-neohesperidoside, astragalin, isorhamnetin-3-O-β-d-glucoside, naringenin, kaempferol and isorhamnetin) in rat plasma. Puerarin was selected as the internal standard. Precipitation of the protein method with acetonitrile was used to extract these flavonoids from the rat plasma samples. The analysis was carried out on an Eclipse plus C column (4.6 mm×100mm, 1.8μm) when acetonitrile and formic acid aqueous solution (0.1%) was used as the mobile phase at a flow rate of 0.3mLmin A tandem mass spectrometer having an electrospray ionization (ESI) source was used to detect eight flavonoids using multiple reaction monitoring (MRM) in the negative ionization mode. The LLOQs for catechin, typhaneoside, isorhamnetin-3-O-neohesperidoside, astragalin, isorhamnetin-3-O-β-d-glucoside, naringenin, kaempferol and isorhamnetin are 4, 4, 4, 0.8, 1, 0.4, 2 and 0.2ngmL, respectively. The precision, accuracy and recovery were all within acceptable limits and the analytes were stable in plasma for all conditions tested. The method was successfully applied to pharmacokinetic study of four flavonoids in rat plasma after administering Pollen Typhae extract orally to rats.