| Abstract: | The present study was designed to explore pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin in healthy and Vibrio alginolyticus-infected large yellow croaker (Pseudosciaena crocea) after a single 10 mg/kg oral dose. Concentrations of enrofloxacin and ciprofloxacin in serum, liver, kidney, muscle and skin of fish were determined using high-performance liquid chromatography. Pharmacokinetic parameters were analysed based on classical compartmental model analysis. The overall changes in enrofloxacin concentration–time curves in serum and tissues of diseased fish were similar to those of healthy fish. However, the peak concentration and peak time of enrofloxacin in serum and tissues were different in healthy and diseased fish. A delay of enrofloxacin peak time in serum and all tissues appeared in the diseased fish. The peak concentrations in serum and tissues of the diseased fish were lower than those of healthy fish. In healthy fish, the area under the concentration–time curve (AUC) was in the order serum >liver > kidney >muscle > skin, while AUC was serum >live > muscle >kidney > skin in the diseased fish. The peak concentrations of ciprofloxacin in the liver, serum, kidney, muscle and skin of healthy fish were 0.93 μg/g, 0.55 μg/ml, 0.36 μg/g, 0.37 μg/g and 0.12 μg/g respectively. Tmax of ciprofloxacin in the corresponding tissues was 8, 24, 12, 12 and 16 h respectively. In the diseased fish, the peak concentrations of ciprofloxacin in the corresponding tissues were 0.52 μg/g, 0.52 μg/ml, 0.41 μg/g, 0.27 μg/g and 0.13 μg/g respectively. Tmax in the corresponding tissues were 0.5, 8, 12, 16 and 48 h respectively. These data indicate that the health status of fish affects drug absorption and metabolism. |
