Abstract: This experiment was to establish a method for the determination of idazoxan hydrochloric in deer plasma by RP-HPLC, and to discuss pharmacokinetics of idazoxan hydrochloric in deer. Six clinical healthy Cervus nippon Temmincks (breed in a room) were injected with the idazoxan solution at the dose of 044 mg·kg^-1. 8 mL blood sample was taken from a jugular vein and plasma was separated for drug analysis using high liquid chromatography with ultraviolet detection. The results showed that the kinetics of idazoxan hydrochloric was fitted to one compartment model with first order absorption by route of administration. The main pharmacokinetic parameters were as follows: the halflives of absorption (t1/2ka) and elimination (t1/2ke) were (2.09±0.34) and (13.18±0.24) min, respectively, area under the plasma drug concent ration-time curve from 0 to ∞(AUC) was (70±3.50) (μg·mL^-1)·min, the peak plasma concent ration (Cmax ) was (4.70±0.50) μg·mL^-1, peaking at (12.46±0.12) min after dosing. The results indicated that idazoxan hydrochloric is characterized by rapid drug action，fast metabolism with little residue in the blood.

Key words: idazoxan hydrochloric, plasma concentration, pharmacokinetics, RPHPLC, deer