Gorden P J, Burchard M, Ydstie J A, Kleinhenz M D, Wulf L W, Rajewski S J, Wang C, Gehring R, Mochel J P, Coetzee J F
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
Pharmacology Analytical Support Team (PhAST), Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
J Vet Pharmacol Ther. 2018 Jun;41(3):463-468. doi: 10.1111/jvp.12488. Epub 2018 Feb 11.
The objective of this study reported here was determine whether differences occurred in meloxicam pharmacokinetics between postpartum cows and mid-lactation cows. Preliminary data from a separate study (P. J. Gorden, unpublished data) in postpartum cows demonstrated elevated plasma and milk concentration profiles compared to previously published data (Malreddy, Coetzee, KuKanich, & Gehring, ). Two different groups were enrolled, each with 10 cows. The treatment group (TRT) was postpartum cows treated with meloxicam, and the positive control (PC) group was cows in mid-lactation treated with meloxicam. Plasma and milk meloxicam concentrations between the TRT and PC group were compared. Significant differences in meloxicam concentration in plasma were determined at all time points from 8 hr to 120 hr post-treatment. In milk, there was a treatment (p = .003), time (p < .001), and treatment by time interaction (p < .001). Significant differences in milk meloxicam concentration were determined at all time points from 8 hr to 96 hr post-treatment, except for the 16-hr time point. The time needed for meloxicam to no longer be detected in milk of the TRT group was longer compared to the PC group, indicating that a longer milk withdrawal is needed. These data suggest higher bioavailability as the underlying mechanism. Further research is needed to determine the mechanisms underlying differences this outcome.
本研究报告的目的是确定产后奶牛和泌乳中期奶牛之间美洛昔康的药代动力学是否存在差异。来自另一项针对产后奶牛的单独研究（P.J.戈尔登，未发表数据）的初步数据表明，与先前发表的数据（马尔雷迪、库切、库卡尼奇和格林， ）相比，血浆和乳汁浓度曲线有所升高。招募了两个不同的组，每组有10头奶牛。治疗组（TRT）是接受美洛昔康治疗的产后奶牛，阳性对照组（PC）是接受美洛昔康治疗的泌乳中期奶牛。比较了TRT组和PC组之间血浆和乳汁中美洛昔康的浓度。在治疗后8小时至120小时的所有时间点，均确定血浆中美洛昔康浓度存在显著差异。在乳汁中，存在治疗（p = 0.003）、时间（p < 0.001）以及治疗与时间的交互作用（p < 0.001）。除了16小时时间点外，在治疗后8小时至96小时的所有时间点，均确定乳汁中美洛昔康浓度存在显著差异。与PC组相比，TRT组乳汁中不再检测到美洛昔康所需的时间更长，这表明需要更长的撤药期。这些数据表明更高的生物利用度是潜在机制。需要进一步研究以确定这一结果差异背后的机制。
