Pharmacokinetics of gentamicin in laboratory rabbits

The pharmacokinetics of gentamicin was studied in 5 healthy adult laboratory rabbits of both sexes. Gentamicin sulfate (5% aqueous solution) was administered rapidly (IV) at a dosage of 3 mg/kg of body weight. Venous blood samples were taken at 0 (baseline), 5, 10, 15, and 30 minutes, and 1, 1.5, 2, 2.5, 3, 4, 5, and 6 hours after gentamicin administration. Serum gentamicin concentration was measured by radioimmunoassay. With the aid of a nonlinear least-squares program, the gentamicin concentration data were found to be best described by a 2-compartment model, with r2 = 0.989. Half-life, as determined from the terminal phase, was 56.6 +/- 2.4 (mean +/- SD) minutes. Calculation of total body clearance provided a mean of 1.69 +/- 0.07 ml/min/kg of body weight. Volume of distribution, calculated from the area under the curve for each animal, was 0.138 +/- 0.005 L/kg.