Pharmacokinetic behaviour of enrofloxacin in greater rheas following a single-dose intramuscular administration

The pharmacokinetic behaviour of enrofloxacin in greater rheas was investigated after intramuscular (IM) administration of 15 mg/kg. Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined by high performance liquid chromatography. Enrofloxacin peak plasma concentration (Cmax = 3.30 ± 0.90 μg/mL) was reached at 24.17 ± 9.17 min. The terminal half-life (t1/2λ) and area under the curve (AUC) were 2.85 ± 0.54 h and 4.18 ± 0.69 μg h/mL, respectively. The AUC and Cmax for ciprofloxacin were 0.25 ± 0.06 μg/mL and 0.66 ± 0.16 μg h/mL, respectively. Taking into account the values obtained for the efficacy indices, an IM dose of 15 mg/kg of enrofloxacin would appear to be adequate for treating infections caused by highly susceptible bacteria (MIC90 < 0.03 μg/mL) in greater rheas.