OBJECTIVETo develop an HPLC method to determine vitexin-rhamnoside in plasma of Beagle dogs and study the pharmacokinetics and bioavailability of Yixintong sustained release tablets in Beagle dogs.

METHODA newly-developed HPLC method using C18 column and methanol-acetonitrile-tetrahydrogenfuran-0.5% acetic acid (1:1:19.4:78.6) as mobile phase was validated, and then was employed to determine vitexin-rhamnoside in plasma of Beagle dogs after oral administration of Yixintong sustained release tablets and general tablets. The main pharmacokinetic parameters were estimated by pharmacokinetic program 3p87. The non-compartmental pharmacokinetic parameters were also calculated on basis of the statistic moment theory.

RESULTThe pharmacokinetic profiles of Yixintong sustained release tablets and the general tablets were fitted to a one-and two-compartment open model, respectively. The T1/2, Tmax, AUC0-infinity and MRT for Yixintong sustained release tablets were 5.22 h, 4.0 h, 6,792.75 ng x h x mL(-1) and 8.4 h, respectively, compared with 8.94 h, 1.0 h, 5,880.4 ng x h x mL(-1) and 6.1 h for the general tablets. The relative bioavailability of the Yixintong sustained release tablets was 115.5% in Beagle dogs.

CONCLUSIONThe sustained-release characteristic of Yixintong sustained release tablets were confirmed by pharmacokinetic study.