Abstract:Danofloxacin, a third generation member of the quinolone family, it has been also used widely to prevent or treat bacterial diseases in fish farming in many countries. It has been studied in Paralichthys olivaceus, Acipenser schrenckii, and goldfish Carassius auratus Linnaeus, etc. However, to our knowledge, there are no studies concerning the pharmacokinetics of danofloxacin in turbot Scophthalmus maximus. In this study, the pharmacokinetics behavior of danofloxacin in turbot after intravenous and oral administration was investigated. Six fish were randomly selected from the tank (water temperature 16±0.6℃) and sampled at 15, 30min, and 1, 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96h after intravenous and oral administration, respectively. The concentrations of danofloxacin were determined by HPLC. The data were analyzed with the pharmacokinetic program DAS 2.0. The results showed that the relationship of plasma concentration versus time for danofloxacin were best described as a two-compartment open model, and the pharmacokinetic equations were: Civ=45.741e-1.927t＋7.332e-0.019t, Cpo=6.796e-0.05t＋3.135e-0.005t－9.931e-0.11t. After the intravenous and oral administration, the main pharmacokinetic parameters were as follows: t1/2β 36.336h and 129.228h, AUC0-96h 431.981 and 284.915 h·μg/ml, respectively. After oral administration, the concentration of danofloxacin in liver and kidney was higher than in muscle, but was similar with the concentration in plasma. According to the danofloxacin pharmacokinetics and the minimal inhibitory concentration of most fish bacterial pathogens, the dosage regime of danofloxacin for treatment of fish bacterial diseases was calculated as a daily dosage of 12.17mg/kg by oral administration.
