Serum concentrations and tissue residues of spectinomycin in chickens.

Following a single intramuscular injection of 40 mg spectinomycin/kg.b.wt. in normal chickens, a maximum serum concentration was recorded at one hour, with half-lives of absorption {[}t(0.5(ab))] and elimination {[}t(0.5(beta))] valued with 0.21 h and 3.27 h respectively. Following a single intravenous injection of 40 mg spectinomycin/kg b. wt. in normal chickens, the drug obeyed a three compartments open model. The mean systemic bioavailability following intramuscular injection was 3.72 \%. The highest serum concentration of spectinomycin was achieved after one hour post each intramuscular dose during multiple dosage regimen. Serum and tissue concentrations of spectinomycin in slaughtered normal chickens following repeated intramuscular administration, three times daily for five consecutive days were investigated. In the present study, spectinomycin was bound in vitro with normal chicken serum protein at a level equal to 5.4 \%.