Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Veterinary Pharmacology

A study of tylvalosin pharmacokinetics was conducted in healthy, health pretreated with prebiotic, Mycoplasma gallisepticum-infected and Mycoplasma gallisepticum-infected pretreated with prebiotic broiler chickens. Tylvalosin was administered intravenously and orally as a single dose of (25 mg/kg b.wt.) to determine its concentrations in blood as well as its kinetic disposition, the oral dose was repeated for 5 consecutive days to determine the tissues residues. The serum concentration - time curve indicated a two-compartment open model. Following intravenous injection, the mean elimination half-lives (t1/2{uF062}) of (6.666±0.285, 6.501±1.143, 3.048±0.232 and 4.284±0.204 h) The apparent volume of distribution (Vd(area)) of tylvalosin was (3.802±0.148, 6.362±0.390, 0.657±0.367 and 6.080±2.928 L/Kg) with body clearance CLÝ (0.953±0.040,1.792±0.062, 1.976±0.743 and 3.592±0.532 L/kg/h) with mean of MRT was (9.314±0.407, 7.533±0.735, 1.739±0.779 and 4.853±0.388 h) in four groups, respectively. Following oral administration, tylvalosin was absorbed with (t{u00BD}Ü) of (0.963±0.045, 0.906±0.025, 0.958±0.207 and 0.956±0.030 h) with peak serum concentration (Cmax) of (1.226±0.024, 0.873±0.009, 0.0760±0.024 and 0.854±0.020 og/ml) at (tmax) of (1.723±0.041, 1.441±0.023, 1.310±0.055 and 1.472±0.025 h) and eliminated with (t{u00BD}Ý) of (3.504±0.049, 3.600±0.165, 3.862±0.103 and 3.132±0.114 h) in four groups, respectively. The systemic bioavailability of Tylvalosin (F%) following oral administration was (47.491±0.538, 52.853±0.416, 72.96±0.003 and 88.652±6.714 %) in four groups, respectively. After single intravenous and oral dose the highest level of drug was concentrated in lung tissue comparable with other tissues, and after repeated oral doses the drug was still detected in lung tissue after 196 hour of the last dose while it is not detected in other tissues

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