Cummings L E, Guthrie A J, Harkins J D, Short C R
Department of Veterinary Physiology, Pharmacology, and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803.
Am J Vet Res. 1990 Dec;51(12):1988-92.
Gentamicin sulfate, equivalent to 4 mg of gentamicin base/kg of body weight, was administered IV to 6 Thoroughbred foals on day 1 (12 to 24 hours of age) and at 5, 10, 15, and 30 days after birth. On day 40 after parturition, gentamicin was given to the mares at a dosage similar to that used in foals. Decay of serum gentamicin concentrations was best described by a 2-compartment model. Among foals, the overall elimination rate constant at 30 days of age was significantly (P less than 0.05) greater than at days 1, 10, and 15. There was, however, no difference in the overall elimination rate constant between foals and mares. The volume of distribution (Vd), determined on the basis of total area under the disposition curve, did not change between day 1 and day 30. Mean values of Vd of foals were between 1.5 and 2.5 times higher than the mean Vd of the mares; however, only values from the foals at days 5 and 10 were significantly greater. Both age and interindividual differences were reflected in the total body clearance (ClB) of gentamicin. Total body clearance of gentamicin of foals on day 1 was less than that of foals on days 5, 10, and 30. Additionally, C1B of gentamicin on day 15 was less than that on day 30. There was no significant difference between ClB of foals and mares except for the day-30 group, which had a higher clearance rate than did the adults. Protein binding of gentamicin was less than 30% in all groups, and there were no apparent age-related differences.
在出生第1天（12至24小时龄）以及出生后5、10、15和30天，给6匹纯种马驹静脉注射相当于4毫克庆大霉素碱/千克体重的硫酸庆大霉素。在分娩后第40天，以与驹相同的剂量给母马注射庆大霉素。血清庆大霉素浓度的衰减情况用二室模型描述最为合适。在驹中，30日龄时的总体消除速率常数显著（P小于0.05）高于1、10和15日龄时。然而，驹和母马之间的总体消除速率常数没有差异。根据处置曲线下的总面积确定的分布容积（Vd）在第1天和第30天之间没有变化。驹的Vd平均值比母马的平均Vd高1.5至2.5倍；然而，只有第5天和第10天驹的值显著更高。庆大霉素的总体清除率（ClB）反映了年龄和个体间差异。驹在第1天的庆大霉素总体清除率低于第5、10和30天的驹。此外，第15天庆大霉素的ClB低于第30天。除了第30天的组清除率高于成年组外，驹和母马的ClB之间没有显著差异。所有组中庆大霉素的蛋白结合率均低于30%，且没有明显的年龄相关差异。
