Pharmacokinetics and Tissue Residues of Tylosin in Broiler Chickens

The pharmacokinetics and tissue residue of tylosin in broiler chickens were studied after I.V. and oral administrations in a dose of 50 mg tylosin/kg.b.wt. Tylosin was obeyed a two-compartment open model following I.V. administration at a dose of 50 mg/kg.b.wt. The disposition kinetics of tylosin following I.V. administration revealed that tylosin was highly distributed with Vd(area) of 6 L/kg and eliminated with half-life (t1/2β) equal to 7.29 hours. The disposition kinetics of tylosin following oral administration revealed that the maximum blood concentration (Cmax) was 3.40 μg/ml attained at (tmax) of 1.08 hour. Tylosin was eliminated with half-life (t1/2β) equal to 5.78 hours. The mean systemic bioavailability of tylosin after oral administration was 90.29%. Following repeated oral administration of 50 mg tylosin base/kg.b.wt once daily for 5 consecutive days, the blood (μg/ml) and tissue (μg/g) residues of tylosin showed that liver, kidney and lung contained the highest tylosin residues and completely disappeared from those tissues at 6 days after the last oral dose. Chickens should not be slaughtered for human consumption within the treatment and 6 days after the last oral administrations of tylosin.