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The pharmacokinetic properties of difloxacin following intravenous (iv) and intramuscular (im) administration in goats were investigated. Difloxacin was administered in a single dose of 5 mg/kg body weight for both routes and was assayed in biological fluids (serum and urine) to determine its concentrations, kinetic behaviour and systemic availability. Following a single iv injection, the serum difloxacin level was best approximated to follow a two-compartment open model using weighted non-linear regression analysis. The elimination half-life (t1/2 beta) was 6.3+/-0.11 h. The volume of distribution at steady-state (Vdss) was 1.1+/-0.012 L/kg and the total body clearance (Cltot) was 0.13+/-0.001 L/kg/h. Following a single im administration, difloxacin was rapidly absorbed and the mean peak serum concentration (4.1+/-0.23 micrograms/ml) was achieved 1 h post administration. The extent of serum protein binding of difloxacin in goats was 13.79+/-1.02% and the systemic availability was 95.4+/-1.17%. Following im injection of difloxacin at a dose rate of 5 mg/kg b. wt for 5 consecutive days, the drug could not be detected in serum and urine at 4th day from the last injection.