The pharmacokinetics (after single oral, i.m. and i.v. administration) and tissue residues after repeated oral (daily for five days) and i.m. (daily for two days) administration of apramycin were investigated in healthy broiler chickens. Apramycin was administered at a dose level of 25 mg/kg b. wt. (for oral and i.m. administration) and at 10 mg/kg b. wt. for i.v. injection. Seventy clinically healthy Hubbard chickens of 1.65~2 kg b.wt. and of 45 days old, were used in the current study. The maximum plasma concentrations of apramycin were achieved 0.18 and 0.70 h after oral and i.m. administration with an absorption half-life (t1/2ab.) of 0.11 and 0.18 h and an elimination half-life (t1/2β) of 1.23 and 2.33 h, respectively. The systemic bioavailability was 2.5 and 60.5 % after oral and i.m. administration, respectively, indicating poor oral absorption of apramycin. After i.v. injection, the pharmacokinetics of apramycin was best described by a two-compartment open model with a t1/2α of 1.55 h, tl/2β of 2.15 h, Vdss of 4.85 litre/kg and Clβ of 1.9 litre/kg/h. The plasma protein binding of apramycin was 25.0 ± 2.45 %. The highest tissue concentrations of apramycin were present in kidneys and liver. No apramycin residues were detected in tissues after 6 h except in liver and kidneys following oral dosing. |
