AIM OF STUDY: The objective of this study was to observe the systemic exposure of quercetin (QCT) including its free and total concentration in rat blood samples following a single p.o. dose of feng-liao-chang-wei-kang granules (FLCWKG). MATERIALS AND METHODS: Six male rats were given the FLCHKG and the serial blood samples were collected. Fully or partially validated LC/MS/MS methods were developed to analyze the resulting biosamples. Various pharmacokinetic (PK) parameters were estimated from the plasma concentration versus time data using non-compartmental methods. RESULTS: Both methods for analysis of the free and total QCT plasma concentration are sensitive, specific, accurate and reliable. The PK parameters of free QCT after administration of FLCWKG, in comparison with total concentration, show a lower C(max) (32.4±8.2 ng/ml versus 164±49 ng/ml), a lower AUC(0→∞) (39.3±6.9 ng/ml h versus 313±16 ng/ml h), a shorter T(max) (0.17±0.00 h versus 0.83±1.01 h) and a similar t(1/2) (3.90±0.88 h versus 3.10±1.94 h), MRT(0→t) (2.27±0.10 h versus 2.86±0.41 h). CONCLUSIONS: Free QCT was quickly absorbed from gastrointestinal tract and circulated in blood at quite low concentration. The circulating flavonoids originating from this formula were dominantly conjugated derivatives. Copyright Â
AIM OF STUDY: The objective of this study was to observe the systemic exposure of quercetin (QCT) including its free and total concentration in rat blood samples following a single p.o. dose of feng-liao-chang-wei-kang granules (FLCWKG). MATERIALS AND METHODS: Six male rats were given the FLCHKG and the serial blood samples were collected. Fully or partially validated LC/MS/MS methods were developed to analyze the resulting biosamples. Various pharmacokinetic (PK) parameters were estimated from the plasma concentration versus time data using non-compartmental methods. RESULTS: Both methods for analysis of the free and total QCT plasma concentration are sensitive, specific, accurate and reliable. The PK parameters of free QCT after administration of FLCWKG, in comparison with total concentration, show a lower C(max) (32.4±8.2 ng/ml versus 164±49 ng/ml), a lower AUC(0→∞) (39.3±6.9 ng/ml h versus 313±16 ng/ml h), a shorter T(max) (0.17±0.00 h versus 0.83±1.01 h) and a similar t(1/2) (3.90±0.88 h versus 3.10±1.94 h), MRT(0→t) (2.27±0.10 h versus 2.86±0.41 h). CONCLUSIONS: Free QCT was quickly absorbed from gastrointestinal tract and circulated in blood at quite low concentration. The circulating flavonoids originating from this formula were dominantly conjugated derivatives. Copyright Â