Abstract
1. The pharmacokinetics and bioavailability of levofloxacin in turkeys were investigated after a single intravenous (IV), intramuscular (IM) and oral (PO) administration of 10 mg/kg body weight.
2. The concentrations of levofloxacin in plasma samples were assayed using a microbiological assay method and pharmacokinetic parameters were calculated by non-compartmental analysis.
3. Following IV administration, the elimination half-life (t0.5(β)), volume of distribution at steady state (Vdss) and total body clearance (Cl) were 4.49 h, 1.31 l/kg and 0.23 l/h/kg, respectively.
4. After single IM and PO administrations at the same dose, levofloxacin was rapidly absorbed as indicated by an absorption half-life (t0.5ab) of 1.02 and 0.76 h, respectively; maximum plasma concentrations (Cmax) of 5.59 and 5.15 μg/ml were obtained at a maximum time (Tmax) of 2 h for both routes and levofloxacin bioavailability (F) was 96.5 h and 79.9% respectively after IM and PO administration. In vitro plasma protein binding of levofloxacin was 24.3%.
5. Based on these pharmacokinetic parameters, a dose of 10 mg/kg body weight given intramuscularly or orally every 24 h in turkeys can maintain effective plasma concentrations with bacterial infections with (minimum inhibitory concentration) MIC90 > 0.1 μg/ml.
ACKNOWLEDGEMENT
The authors wish to thank Prof. Dr Ashraf Elkomy (Department of Pharmacology, Faculty of Veterinary Medicine, Benha University, Egypt) for his comments on the manuscript.