Disposition of single-dose intravenously administered amikacin in emus (Dromaius novaehollandiae)

The pharmacokinetics of amikacin in emus (Dromaius novaehollandiae) was examined following parenteral administration. A mean 7.2 +/- 0.12 mg/kg dose was administered as a single i.v. bolus, and serum samples were collected at predetermined intervals over a 24-hr period. Amikacin levels were measured using a fluorescence polarization immunoassay, and the resulting concentration-versus-time curve was analyzed using nonlinear regression with least squares parameter estimation. The data were best represented by a three-compartment model with a mean elimination half-life (t(1/2)beta) of 0.87 hr, with a longer rate of elimination from the third compartment (t(1/2)gamma = 6.06 hr). Mean model-independent parameters obtained were area under the curve (269.66 mu g.hr/ml), mean residence time (6.48 hr), apparent volume of distribution (0.18 L/kg), and total body drug clearance (0.03 L/hr/kg). Mean serum concentrations exceeded a target peak of 32.0 mu g/ml and remained above an estimated inhibitory concentration of 8.0 mu g/ml for approximately 12 hr. Mean serum levels had declined below a target trough of 4 mu g/ml at 24 hr.