Comparative pharmacokinetics of florfenicol in the chicken, pigeon and quail.

1. The pharmacokinetics of florfenicol were investigated in chickens (n = 20), pigeons (n = 30) and quails (n = 60) following intravenous (i.v.) and intramuscular (i.m.) administration of 30 mg/kg body weight. The concentration of florfenicol was measured using high performance liquid chromatography with ultraviolet detection. 2. The plasma concentrations following administration of the drug by both routes were lower in pigeons and quails than in chickens for the whole sampling period. 3. Following i.v. administration, plasma concentration over time was best described by a two-compartment open model. The elimination half-life (t(1/2)(beta)), mean residence time (MRT), total body clearance (Cl(B)), area under the plasma concentration curve (AUC(0-infinity)) were different in chickens, pigeons and quail. The distribution half-life (t((1/2))(alpha)) and volume of distribution (V(dss)) were similar in all species studied. 4. Plasma concentration time data after i.m. administration was adequately described by one-compartment open model. The elimination half-life (t((1/2)el)), mean residence time (MRT), maximum plasma concentration (C(max)) and area under the plasma concentration curve (AUC(0-infinity)) were significantly different in chickens, pigeons and quail. Mean absorption time (MAT), time to maximum concentration (T(max)), absorption half-life (t((1/2)ab)) and systemic bioavailability (F) were similar in the three species. 5. Species differences in florfenicol elimination exist. Doses and treatments should not be extrapolated from chickens to pigeons and quails without pharmacokinetic data.