Pharmacokinetics of difloxacin in Japanese quails (Coturnix japonica) after single intravenous and oral administration

Pharmacokinetics of difloxacin (DF), a fluoroquinolone antibiotic, were investigated in Japanese quails (Coturnix japonica) after a single intravenous (IV) and oral (PO) administration of 10 mg/kg bodyweight. Plasma concentration profiles of DF were analyzed by a compartmental pharmacokinetic method. Following IV injection, the plasma concentration vs time profile was best described by a two-compartment open model. Elimination half-life (t(1/2 beta)), total body clearance (Cl-tot), volume of distribution at steady state (V-dss) and mean residence time (MRT) of DF were 5.45 +/- 0.14 h, 0.22 +/- 0.01 L/kg/h, 1.54 +/- 0.06 L/kg and 6.92 +/- 0.19 h, respectively. Following PO administration, DF was rapidly absorbed, with peak plasma concentration (C-max) of 3.67 mu g/mL attained at 1.90 h (T-max) after administration. Absorption half-life (t(1/2ab)) elimination half-life (t(1/2el)), mean, absorption time (MAT) were 0.5 h, 5.26 h and 1.11 h, respectively. The bioavailability (F) following PO administration of DF was high (84.40%). For a successful clinical effect of DF in quails, a multiple dosage regimen of 10 mg/kg bodyweight, administered orally every 24 h is recommended to maintain effective plasma concentrations with bacterial infections, in which MIC90 is < 0.2 mu g/mL.