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: CMax (obs) 70.6 ± 14.6 µg/mL, TMax (obs) 2.9 ± 1.5 h, elimination rate constant (kel ) 0.017 ± 0.002/h, elimination half-life (t1/2kel) 41.6 ± 4.7 h, area under the plasma concentration-vs.-time curve to last sample (AUClast) 3438.7 ± 437.7 h·µg/mL and AUC extrapolated to infinity (AUC0→∞ ) 3447.8 ± 439.0 h·µg/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.