DISPOSITION KINETICS OF DIFLOXACIN IN NORMAL AND EXPERIMENTALLY INFECTED CHICKENS WITH MYCOPLASMA GALLISEPTICUM

The pharmacokinetic properties of difloxacin were investigated follo-wing intravenous, intramuscular and oral administration of 10 mg/kg body weight, in non-infected and experimentally mycoplasma infected chickens. Serum concentrations of difloxacin were assayed microbial-ogically after intravenous, intramuscular and oral administrations. difl-oxacin residues were detected in chicken tissues following repeated oral administrations in non-infected and infected chickens. Following a single intravenous injection, the serum difloxacin level was best approximated to follow a two-compartment open model. The elimination half-life (t0.5b) was 4.58 + 0.008 h. The volume of distri-bution at steady-state (Vdss) was 2.12 + 0.07 L/kg and the mean resid-ence time (MRT) was 3.91 + 0.07 h. Following a single oral administration of 10 mg/kg b.wt difloxacin,the recorded results revealed that serum level of difloxacin was higher in infected chickens than non infected chickens. Serum concentrations peaked one hour post-drug administration with half lifes of absorption (t0.5ab) of 0.48 + 0.02 and 0.37 + 0.02 hour in non infected and myc-oplasma infected chickens, respectively. The extent of serum protein binding of difloxacin in non-infected chickens was 15.44 + 1.24%. Systemic bioavailability after oral and intramuscular administration of difloxacininnon-infectedchickenswas75.87and 93.03%,respectively. Following oral and intramuscular administration of 10 mg difloxacin / kg b.wt once daily for 5 consecutive days in infected and non infected chic-kens, the drug could be detected in all tested tissue up to 48 hours after last oral and intramuscular dose in non infected and infected chickens.