Scott E W, McKellar Q A
Department of Veterinary Pharmacology, University of Glasgow Veterinary School, Bearsden, UK.
Vet Res Commun. 1992;16(2):139-46. doi: 10.1007/BF01839011.
Ivermectin was injected subcutaneously into five pigs at the usual dose rate of 300 micrograms/kg and found to distribute well to all tissues and body fluids which were sampled 24 h post-injection. Ivermectin was detected in the contents and mucus at all levels of the gastrointestinal tract. The drug was excreted in bile, with high concentrations of the drug in the intestines and faeces. High concentrations of ivermectin were measured in skin, ears and ear wax, suggesting that the drug should be effective in the treatment of ectoparasitic infestations, particularly ear mites. The high lipid solubility of the drug may explain the high concentrations found in ear wax and skin. Ivermectin was also detected in the body fluids and tissues of an untreated pig penned with the treated animals. Direct contact appeared to be necessary for transfer of ivermectin from the treated to the untreated pig but coprophagia or urine drinking is a possible explanation. The pharmacokinetics of ivermectin administered subcutaneously at a dose rate of 300 micrograms/kg to six pigs were studied. There was marked individual variation in the pharmacokinetics of ivermectin. In one pig the area under the plasma concentration-time curve was particularly high. This may reflect individual variation in uptake and excretion of the drug. The mean elimination half-life of the drug was 35.2 h, suggesting that the drug is cleared slowly from pigs with drug detectable in plasma for 6-10 days. This persistence should allow a short period of protection before re-infection with parasites.
以300微克/千克的常用剂量率将伊维菌素皮下注射到5头猪体内，发现其在注射后24小时分布到所有采样的组织和体液中。在胃肠道各部位的内容物和黏液中均检测到伊维菌素。该药物经胆汁排泄，在肠道和粪便中有高浓度的药物。在皮肤、耳朵和耳垢中检测到高浓度的伊维菌素，这表明该药物在治疗外寄生虫感染，特别是耳螨方面应该有效。药物的高脂溶性可能解释了在耳垢和皮肤中发现的高浓度。在与经治疗动物圈养在一起的一头未治疗猪的体液和组织中也检测到了伊维菌素。伊维菌素从经治疗猪转移到未治疗猪似乎需要直接接触，但食粪或饮尿也是一种可能的解释。研究了以300微克/千克的剂量率对6头猪皮下注射伊维菌素的药代动力学。伊维菌素的药代动力学存在明显的个体差异。在一头猪中，血浆浓度-时间曲线下面积特别高。这可能反映了药物吸收和排泄的个体差异。该药物的平均消除半衰期为35.2小时，这表明该药物在猪体内清除缓慢，血浆中药物可检测6至10天。这种持续性应能在再次感染寄生虫之前提供一段短暂的保护期。
