Abstract: AIM: Toestablishapliannacokinetio pharmacodynamic (PK-PD) model to analyze the relation between the plasma concentration of dauricine and the ef-fect on electrocardiogram (ECG) in 4 Beagle dogs. METHODS: 8 hours after intravenous administration of 6 mg·kg^-1 dauricine, blood was serially sampled and the effect on electrocardiogram was measured. The plasma concentration of dauricine was measured by HPLC-ultravi-olet method. The time courses of plasma concentration and the effects of dauricine were analyzed with 3P97 pro-gram and PK-PD parameters estimate program · RE-SULTS: The plasma concentration-time course followed a 2-compartment open model. The mean distribution half-life (t_1/2α) was 0.049±0.016 h and terminal elimination half-life (t_1/2β) was 2.7±0.6 h. The maximal decrease in heart rate (HR) was (26.4±6.1)%,whereas the maximal increase in PR, QRS, and Q-Tc intervals were (33,7±10.0)%,（35.6±12.0)% and (25.5±9.4)%, respectively. All peak effects were appeared ap-proximately 10-15 minutes after intravenous administra-tion of dauricine. Effect on electrocardiogram was ana-lyzed by the effect-link sigmoid model. CONCLUSION: The PK-PD model can successfully characterize the relation between the plasma concentrations of dau-ricine and the effect on electrocardiogram.

Key words: dauricine, pharmacokinetics, pharmaco-dynamics, pharmacokinetic-pharmacodynamic (PK-PD)