Investigation on the absorption kinetics of chlorogenic acid in rats by HPLC.

Chlorogenic acid (ChA), a major phenolic compound in the Flos Lonicerae, is widely used in the traditional Chinese medicine practice. The purpose of this study is to report the pharmacokinetic parameters of ChA in rats after oral administration and explore its absorption profile briefly. A two-compartment model was proposed and validated through the program to explain the apparent triphasic phenomenon of ChA in rats after intragastric administration. A rapid absorption and a relatively slow distribution followed by a slower elimination phase were observed. At the administered doses of 200, 400 and 600 mg/kg, the values of absorption half-life (t 1/2 Ka) were 10.23, 18.66 and 28.13 min. The values of distribution half-life (t1/2) were 12.35, 31.04 and 39.19 min. And the values of elimination half-life (t1/2P) were 231.64, 337.23 and 420.81 min. The volume of distribution at the three doses were 55.26, 35.56, 32.22 L/kg, respectively. The AUC0-->infinity (area under the concentration-time curve) was not proportional to the administered dose. In the range of the doses examined, the absorption pharmacokinetics of ChA in rats was based on nonlinear kinetics.