Pharmacokinetics and absolute bioavailability of gallic acid in rat plasma

Objective To develop a method for the quantitative determination of gallic acid in rat plasma by high performance liquid chromatography(HPLC),and study the pharmacokinetics and absolute bioavailability in rats.Methods Acetaminophen was selected as internal standard,and the plasma samples were pretreated by protein precipitation with methanol.Phenomenex C18 was used with the mobile phase of methanol and water contained 0.5% glacial acetic acid(V∶V=7∶93) at a flow rate of 1.0 mL·min-1,and detection wavelength was set at UV 272 nm.Results After ig of gallic acid,the values of t1/2α,t1/2β,tmax,ρmax and AUC0-t were 46.57 min,56.54 min,66.00 min,3.96 mg·L-1 and 396.5 mg·min·L-1,respectively;As for iv,t1/2α,t1/2β and AUC0-t,the values were 9.90 min,78.88 min and 461.9 mg·min·L-1,respectively.Conclusions The concentration-time curves of gallic acid in rats after ig and iv administration shows that they both fit two-compartment model.Absolute bioavailability of gallic acid is 42.9%.