Pharmacokinetics of ceftiofur crystalline free acid after single and multiple subcutaneous administrations in healthy alpacas (Vicugna pacos)

Dechant, J. E., Rowe, J. D., Byrne, B. A., Wetzlich, S. E., Kieu, H. T., Tell, L. A. Pharmacokinetics of ceftiofur crystalline free acid after single and multiple subcutaneous administrations in healthy alpacas (Vicugna pacos). J. vet. Pharmacol. Therap.36, 122129. Six adult male alpacas received one subcutaneous administration of ceftiofur crystalline free acid (CCFA) at a dosage of 6.6mg/kg. After a washout period, the same alpacas received three subcutaneous doses of 6.6mg/kg CCFA at 5-day intervals. Blood samples collected from the jugular vein before and at multiple time points after each CCFA administration were assayed for ceftiofur- and desfuroylceftiofur-related metabolite concentrations using high-performance liquid chromatography. Pharmacokinetic disposition of CCFA was analyzed by a noncompartmental approach. Mean pharmacokinetic parameters (+/- SD) following single-dose administration of CCFA were Cmax (2.7 +/- 0.9g/mL); Tmax (36 +/- 0h); area under the curve AUC0 (199.2 +/- 42.1g center dot h/mL); terminal phase rate constant z (0.02 +/- 0.003/h); and terminal phase rate constant half-life t1/2z (44.7h; harmonic). Mean terminal pharmacokinetic parameters (+/- SD) following three administrations of CCFA were Cmax (2.0 +/- 0.4g/mL); Tmax (17.3 +/- 16.3h); AUC0 (216.8 +/- 84.5g center dot h/mL); z (0.01 +/- 0.003/h); and t1/2z (65.9h; harmonic). The terminal phase rate constant and the Tmax were significantly different between single and multiple administrations. Local reactions were noted in two alpacas following multiple CCFA administrations.