Hall, T. L., Tell, L. A., Wetzlich, S. E., McCormick, J. D., Fowler, L. W., Pusterla, N. Pharmacokinetics of ceftiofur sodium and ceftiofur crystalline free acid in neonatal foals. J. vet. Pharmacol. Therap.34, 403–409.

Ceftiofur, a third generation cephalosporin, demonstrates in vitro efficacy against microorganisms isolated from septicemic neonatal foals. This pharmacokinetic study evaluated the intravenous and subcutaneous administration of ceftiofur sodium (5 mg/kg body weight; = 6 per group) and subcutaneous administration of ceftiofur crystalline free acid (6.6 mg/kg body weight; = 6) in healthy foals. Plasma ceftiofur- and desfuroylceftiofur-related metabolite concentrations were measured using high performance liquid chromatography following drug administration. Mean (±SD) noncompartmental pharmacokinetic parameters for i.v. and s.c. ceftiofur sodium were: AUC0[RIGHTWARDS ARROW] (86.4 ± 8.5 and 91 ± 22 h·μg/mL for i.v. and s.c., respectively), terminal elimination half-life (5.82 ± 1.00 and 5.55 ± 0.81 h for i.v. and s.c., respectively), Cmax(obs) (13 ± 1.9 μg/mL s.c.), Tmax(obs) (0.75 ± 0.4 h for s.c.). Mean (± SD) noncompartmental pharmacokinetic parameters for s.c. ceftiofur crystalline free acid were: AUC0[RIGHTWARDS ARROW] (139.53 ± 22.63 h·μg/mL), terminal elimination half-life (39.7 ± 14.7), Cmax(obs) (2.52 ± 0.35 μg/mL) and tmax(obs) (11.33 ± 1.63 h). No adverse effects attributed to drug administration were observed in any foal. Ceftiofur- and desfuroylceftiofur-related metabolites reached sufficient plasma concentrations to effectively treat common bacterial pathogens isolated from septicemic foals.