Pharmacokinetics and intramuscular bioavailability of cefuroxime sodium ingoats

The pharmacokinetics of cefuroxime sodium, 20 and 40 mg kg(-1), were studie d after i.v. and intramuscular injections in goats. Following single i.v. i njections the serum concentration time curves of cefuroxime sodium were bes t fitted to a two-compartment open model. The drug was rapidly distributed with half-lives of distribution (t(1/2 alpha)) of 0.250 hours and 0.266 hou rs, and rapidly eliminated with half-lives of elimination (t(1/2 beta)) of 1.482 hours and 1.416 hours, respectively, following single i.v. injections of 20 and 40 mg kg(-1) body weight. After single intramuscular injections of cefuroxime sodium at the same doses, the mean absorption time (MAT) valu es were 1.379 and 1.716 hours and the peak serum concentration, C-max, was 12.965 and 38.50 mug ml(-1), attained after 0.515 and 0.608 hours (t(max)), respectively. The elimination half-lives (t(1/2el)) were 2.088 and 2.114 h ours and the mean residence times (MRT) were 3.198 and 3.237 hours for 20 a nd 40 mg kg-l body weight, respectively. After both i.v. and intramuscular injections of cefuroxime sodium, the concentrations of cefuroxime in urine were much higher than that in serum. Urinary drug concentrations decreased gradually to reach their lowest levels at 24 and 48 hours post-injection, r espectively. The systemic bioavailability of cefuroxime sodium in goats aft er intramuscular injections of 20 and 40 mg kg(-1) body weight was 88.4 per cent and 103.5 per cent, respectively. In vitro protein binding of cefurox ime sodium in goat's serum was low, ranging from 13.3 per cent to 21.6 per cent with an average of 17.0 per cent. (C) 2000 Harcourt Publishers Ltd.