Pharmacokinetics of amoxicillin trihydrate in Desert sheep and Nubian goats

The pharmacokinetics of amoxicillin were studied in five Desert sheep and f ive Nubian goats after intravenous (i.v.) or intramuscular (i.m.) administr ation of a single dose of 10 mg/kg body weight. Following i.v. injection, t he plasma concentration-versus-time data were best described by a two-compa rtment open model. The kinetic variables were similar in both species excep t for the volume of the central compartment (V-c), which was larger in shee p (p < 0.05). Following i.m. injection, except for the longer half-life tim e of absorption in goats (p < 0.05), there were no significant differences in other pharmacokinetic parameters between sheep and goats. The route of a moxicillin administration had no significant effect on the terminal elimina tion half-life in either species. The bioavailability of the drug (F) after i.m. administration was high (> 0.90) in both species. These results indic ate that the pharmacokinetics of amoxicillin did not differ between sheep a nd goats; furthermore, because of the high availability and short half-life of absorption, the i.m. route gives similar results to the i.v. route. The refore, identical intramuscular and intravenous dose regimens should be app licable to both species.