Systemic exposure of quercetin after administration of feng-liao-chang-wei-kang granules to rats

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.