Pharmacokinetics of forsythoside after intravenous administration in beagle dogs

A high-performance liquid chromatography with ultraviolet detection method was established and validated for quantification of forsythoside concentrations in dog plasma. Following a single-step protein precipitation with perchloric acid, the forsythoside and internal standard were separated on a reversed-phase C18 column with water-glacial acetic acid-methanol as mobile phase at a flow rate of 1 mL/min with ultraviolet detection at 326 and 278 nm for forsythoside and IS, respectively. The calibration curve for forsythoside was linear over a range of 0.052-13.33 microg/mL with correlation coefficient of 0.999. The within- and between-batch precisions of analysis were < 8 % and accuracy was 95-107%. After intravenous administration of forsythoside at the doses of 5, 10, and 20 mg/kg, the C(max) values for forsythoside were estimated to be of 12.33, 22.90 and 54.45 microg/mL, respectively. The AUC increased with the increasing of doses, and the mean AUC(o-t) values were 5.69, 11.80, and 18.66 mg x h/L, respectively. Forsythoside was eliminated quickly and the mean T(1/2) values at doses of 5, 10, and 20 mg/kg were 1.36, 1.49, and 0.71 h, respectively. The pharmacokinetics of forsythoside in beagle dogs complied with linear kinetic course in the dose range.