308PHARMACOKINETICAL INTERACTIONS OF LINCOMYCIN AND AMPROLIUM IN BROILER CHICKENSPharmacokinetic parameters and bioavailability of lincomycin following a single intravenous and oral administrations were determined in broiler chickens. Effect of amprolium on the disposition kinetics and tissue residues of lincomycin following repeated oral administrations was also investigated. Following a single intravenous injection of lincomycin, 20 mg/kg.b.wt., in normal broiler chickens, plasma concentration-time curve was best described by a twocompartments open model with elimination half-life (t0.5 = 2.93±0.014 h), volume of distribution (Vdss = 1.76±0.014 L/kg) and total clearance of the drug (CLtot = 0.457±0.004 L/kg/h). Following a single oral administration, the maximum plasma concentration was 7.08±0.16 g/ml, reached at maximum time of 1.16±0.02 h. The mean systemic bioavailability following oral administration was 71.32± 2.62%. Following repeated oral administration in normal chickens, highest plasma concentration peaked after one hour of each oral dose. Amprolium resulted in a significant decrease in maximum plasma concentration (C max = 7.29 ± 0.204 g/ml) compared with lincomycin alone (C max = 8.13 ± 0.244 g/ml). Amprolium resulted in a significant decrease in tissue residues of lincomycin. It is concluded that the administration of amprolium before lincomycin in broiler chickens would altered the pharmacokinetic profile of lincomycin. drgehanelsaied @yahoo.comResearch592015Pharmacokinetics,Interaction,Lincomycin,Amprolium,ChickensEl-Sayed,M.G.A,A.A.A.El-Komy,A.M.El-barawy,Gehan,E.A.MustafaDepartment of pharmacology, Faculty of Veterinary Medicine, Benha University, Egypt,Department of pharmacology, Faculty of Veterinary Medicine, Benha University, Egypt,Department of pharmacology, Faculty of Veterinary Medicine, Benha University, Egypt,Department of pharmacology, Animal Health Research Institute, Dokki, Giza, Egypt.,Department of pharmacology, Animal Health Research Institute, Dokki, Giza, Egypt.,Department of pharmacology, Animal Health Research Institute, Benha, Egypt.