Abstract: The norfloxacin（NFX） concentrations in plasma,liver and kidney were monitored 0.15,0.25,0.5,0.75,1,1.5,2,4,6,8,12,24,48,72 h after single intraperitoneal injection of 30 mg NFX /kg bodyweight in rainbow trout Oncorhynchus mykiss with body weight of 100 ± 10 g at a single dosage at water temperature of 15±2℃ by high performance liquid chromatography（HPLC） to study the pharmacokinetics of NFX.The NFX concentrations were shown to be described as a two-compartment open model with 1st order absorption in the plasma,liver and kidney.The T1/2α was found 0.866 h in the plasma,1.985 h in the liver and 0.388 h in the kidney,and the T1/2β was 31.369h in the plasma,36.402h in the liver and 30.975 h in the kidney.The AUC was described as 308.005 μg/mL·h in the plasma,622.721 μg/g·h in the liver,and 794.362 μg/g·h in the kidney.

Key words: Oncorhynchus mykiss, Norfloxacin, pharmacokinetic