Pharmacokinetic indices for cefovecin after single-dose administration to adult sea otters (Enhydra lutris).

Seven sea otters received a single subcutaneous dose of cefovecin at 8 mg/kg body weight. Plasma samples were collected at predetermined time points and assayed for total cefovecin concentrations using ultra-performance liquid chromatography and tandem mass spectrometry. The mean (+/- SD) noncompartmental pharmacokinetic indices were as follows: C-Max (obs) 70.6 +/- 14.6 mu g/mL, T-Max (obs) 2.9 +/- 1.5 h, elimination rate constant (k(el)) 0.017 +/- 0.002/h, elimination half-life (t(1/2kel)) 41.6 +/- 4.7 h, area under the plasma concentration-vs.-time curve to last sample (AUC(last)) 3438.7 +/- 437.7 h.mu g/mL and AUC extrapolated to infinity (AUC(0 ->infinity)) 3447.8 +/- 439.0 h.mu g/mL. The minimum inhibitory concentrations (MIC) for select isolates were determined and used to suggest possible dosing intervals of 10 days, 5 days, and 2.5 days for gram-positive, gram-negative, and Vibrio parahaemolyticus bacterial species, respectively. This study found a single subcutaneous dose of cefovecin sodium in sea otters to be clinically safe and a viable option for long-acting antimicrobial therapy.