Pharmacokinetics of danofloxacin in African catfish (Clarias gariepinus) after intravenous and intramuscular administrations

The plasma pharmacokinetics of danofloxacin was studied in healthy African catfish (Clarias gariepinus) following a single intravenous (IV) and intramuscular (IM) administration of 10 mg/kg at 22 °C. Catfish were divided into two groups (each group containing 78 fish), then danofloxacin mesylate (10 mg/kg) was administered IV (into the caudal vein) in Group 1 and IM (into the right epaxial muscle) in Group 2, and blood was obtained from the caudal vein before (0 h) and after (0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 72 and 96 h) of drug administration. High-performance liquid chromatography was used for the determination of plasma concentration, and a non-compartmental model was used for the analysis of pharmacokinetic parameters. After IV administration, elimination half-life (t1/2λz, 24.49 h), mean residence time (MRT, 30.14 h), volume of distribution at steady state (Vdss, 1.07 L/kg) and total body clearance (CLT, 0.035 L/h/kg) were determined. After IM administration, t1/2λz, MRT, peak concentration (Cmax), time to reach Cmax and bioavailability were 47.64 h, 61.06 h, 5.22 µg/mL, 1 h and 67.12%, respectively. After IM administration, danofloxacin showed good bioavailability and long t1/2λz. The favourable pharmacokinetic characteristics after IM administration support the use of danofloxacin for the treatment of susceptible bacterial infections in catfish