Tissue concentrations and pharmacokinetics of florfenicol in broiler chickens

Florfenicol was once administered to broiler chickens via i.v., i.m. and oral route (30 mg/kg body weight) to study its plasma concentrations, kinetic behaviour, systemic bioavailability and tissue levels. Following a single i. v. injection, the kinetic disposition of florfenicol followed a two-compartmental open model with an elimination half-life of 172 min, total body clearance of 26.9 ml/kg/min and a steady state volume of distribution of 5.11 litre/kg. The highest plasma concentrations of florfenicol were 3.82 and 3.20 micrograms/ml following single i.m. and oral administration, respectively. The systemic bioavailability was 96.6 and 55.3 per cent after i.m. and oral administration. The plasma protein binding of florfenicol was 18.5%. Following the administration, the highest tissue concentration of the drug was found in kidney, bile, lung, muscle, intestine, heart, liver, spleen and serum. Low concentrations of the drug were found in brain, bone marrow and fat. No florfenicol residues were detected in tissues and serum after 72 h except in the bile, it disappeared after 96 h.