Dulin Jennifer A, Drost W Tod, Phelps Mitch A, Santschi Elizabeth M, Menendez Maria I, Bertone Alicia L
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Am J Vet Res. 2012 Mar;73(3):418-25. doi: 10.2460/ajvr.73.3.418.
To determine the effects of exercise on the distribution and pharmacokinetics of technetium Tc 99m medronate ((99m)Tc-MDP) following intra-articular (IA) injection in horses.
5 horses.
1 antebrachiocarpal joint (ACJ)/horse was assigned to the exercised group (n = 5), and the contralateral ACJ was evaluated in the nonexercised group (5) after a minimum washout period of 7 days. Following IA injection of (99m)Tc-MDP (148 MBq), blood and scintigraphic images of the carpus were obtained at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 240, 360, 480, 600, 720, and 1,440 minutes. Plasma and scintigraphic radioactivity were determined over time, and pharmacokinetic parameters were generated via noncompartmental and compartmental analyses. Each horse was monitored via physical and lameness examination and ACJ synovial fluid analysis before injection and at days 1, 2, 3, and 7.
Lameness was not observed. Mean ± SD synovial fluid WBC count increased at day 1 (exercised, 721 ± 234 cells/μL; nonexercised, 948 ± 223 cells/μL), but returned to baseline at days 3 and 7 Mean time to maximum plasma radioactivity was earlier in the exercised group (16.00 ± 2.35 minutes) than the nonexercised group (43.75 ± 3.64 minutes). Linear regression of the scintigraphic radioactivity-time curves revealed a greater negative slope in the exercised group within the first 25 minutes. There was no difference in absorption or elimination rate constants in a 2-compartment model.
IA injection of (99m)Tc-MDP was safe and effective for evaluating synovial solute distribution. Exercise significantly increased early transfer of (99m)Tc-MDP from the ACJ into plasma, although absorption and elimination rate constants were not affected. Exercise may affect synovial clearance and withdrawal times of medications administered IA.
确定运动对马关节内（IA）注射锝 Tc 99m 亚甲基二膦酸盐（（99m）Tc-MDP）后的分布及药代动力学的影响。
5匹马。
每匹马的1个腕掌关节（ACJ）被分配到运动组（n = 5），对侧ACJ在至少7天的洗脱期后在非运动组（n = 5）中进行评估。IA注射（99m）Tc-MDP（148 MBq）后，在5、10、15、20、25、30、45、60、90、120、240、360、480、600、720和1440分钟采集血液和腕关节的闪烁图像。随时间测定血浆和闪烁图像放射性，并通过非房室和房室分析生成药代动力学参数。在注射前以及第1、2、3和7天，通过体格检查、跛行检查和ACJ滑液分析对每匹马进行监测。
未观察到跛行。滑液白细胞计数均值±标准差在第1天增加（运动组，721±234个细胞/μL；非运动组，948±223个细胞/μL），但在第3天和第7天恢复到基线水平。运动组达到最大血浆放射性的平均时间（16.00±2.35分钟）早于非运动组（43.75±3.64分钟）。闪烁图像放射性-时间曲线的线性回归显示，运动组在前25分钟内斜率更负。在二房室模型中，吸收或消除速率常数无差异。
IA注射（99m）Tc-MDP对评估滑液溶质分布安全有效。运动显著增加了（99m）Tc-MDP从ACJ到血浆的早期转运，尽管吸收和消除速率常数未受影响。运动可能影响IA给药的滑液清除率和撤药时间。
