Mosher R A, Coetzee J F, Cull C A, Gehring R, KuKanich B
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
J Vet Pharmacol Ther. 2012 Aug;35(4):373-81. doi: 10.1111/j.1365-2885.2011.01331.x. Epub 2011 Aug 29.
The pharmacokinetics of oral meloxicam has been studied in ruminant, but not preruminant calves. Oral meloxicam was administered at 0.5 mg/kg to six ruminant calves via gavage (RG); to six preruminant calves via gavage (PRG); and to six preruminant calves via suckling in milk replacer (PRF). Plasma drug concentrations, determined over 120-h postadministration, were analyzed by compartmental and noncompartmental methods. The rate of drug absorption was faster (P<0.01) in PRF (0.237±0.0478/h) than RG calves (0.0815±0.0188/h), while absorption in PRG calves (0.153±0.128/h) was not different from other groups. C(max) was lower (P=0.03) in PRF (1.27±0.430 μg/mL) than in PRG calves (2.20±0.467 μg/mL), while C(max) of RG calves (1.95±0.955 μg/mL) was not different from other groups. V/F was higher in PRF calves (365±57 mL/kg) than either PRG (177±63 mL/kg, P<0.01) or RG (232±83 mL/kg, P=0.01) calves. These observations were likely due to differences in bioavailability, physiological maturity, and timing of the drug delivery into different compartments of the ruminant gastrointestinal tract. Results suggest that an adjustment in meloxicam dose may be necessary when administered with milk replacer.
已对反刍动物口服美洛昔康的药代动力学进行了研究，但未涉及反刍前犊牛。以0.5mg/kg的剂量通过灌胃法给6头反刍犊牛（RG组）、通过灌胃法给6头反刍前犊牛（PRG组）以及通过在代乳品中哺乳的方式给6头反刍前犊牛（PRF组）口服美洛昔康。给药后120小时内测定血浆药物浓度，并采用房室和非房室方法进行分析。PRF组（0.237±0.0478/h）的药物吸收速率比RG组犊牛（0.0815±0.0188/h）更快（P<0.01），而PRG组犊牛（0.153±0.128/h）的吸收与其他组无差异。PRF组（1.27±0.430μg/mL）的C(max)低于PRG组犊牛（2.20±0.467μg/mL）（P=0.03），而RG组犊牛的C(max)（1.95±0.955μg/mL）与其他组无差异。PRF组犊牛的V/F（365±57mL/kg）高于PRG组（177±63mL/kg，P<0.01）或RG组（232±83mL/kg，P=0.01）犊牛。这些观察结果可能归因于生物利用度、生理成熟度以及药物进入反刍动物胃肠道不同部位的时间差异。结果表明，当与代乳品一起给药时，可能需要调整美洛昔康的剂量。
