PHARMACOKINETICS OF GENTAMICIN IN THE HORSE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 41  (3) , 351-354
Abstract
The pharmacokinetics of gentamicin were studied in 6 healthy mature horses of mixed breeding and of both sexes. A parenteral preparation of gentamicin sulfate (5% aqueous solution) was administered rapidly (i.v.) at the dosage level of 5 mg/kg of body weight. Venous blood samples were taken at 0 (base line), 0.083, 0.25, 0.5, 0.75, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96 and 120 h after gentamicin administration. Serum gentamicin was measured by a radioimmunoassay technique. The gentamicin concentration data were fitted to a 1- and 2-compartment open model with first-order elimination from the central compartment with the aid of nonlinear least squares program. The data were best described by the 2-compartment model with r2 = 0.997. Half-life, as determined from the terminal phase, was 2.54 .+-. 0.33 h. Calculation of the total body clearance provided a mean of 1.16 .+-. 0.11 ml/min per kg of body weight (1.04-1.31 ml/min per kg; range); the volume of distribution calculated from the area under the curve was determined separately for each animal and had a mean value of 0.254 .+-. 0.036 l/kg. The initial exponential decline (.alpha.) in gentamicin serum concentration had an average value of 3.75 .+-. 1.86 h-1, whereas the terminal values were described by .beta. = 0.275 .+-. 0.036 h-1. Other pharmacokinetic values determined also are presented.