Abstract: Pharmacokinetics studies of pour-on of doramectin in dog blood plasma. Drow blood from the jugular vein of the dogs in different time after used the pour-on of doramectin one time on the skin of back with the concentration 0.1 mg/kg·bw. We used the method of the HPLC to detect the concentration of the doramectin in the blood plasma. The blood plasma doramectin concentration and time data was processed by the non compartment analysis of the WinNonlin5.2.1 software. The main pharmacokinetic parameters were the maximum concentration (C_max) of the doramectin in the blood plasma is (24.38±4.82) ng/mL, and the time is (1.00±0.00) d (T_max)after we used the doramectin pour-on. The elimination half life (t1/2β) is (2.14±0.56) d. Area under curve (AUC) is (89.79±16.90) ng/(d·mL). The results showed that doramectin has a long persistence in the plasma concentrations and eliminated slowly in dogs.

Key words: pharmacokinetics; doramectin; pour-on preparation