Láznícek M, Láznícková A, Budský F
Faculty of Pharmacy, Charles University, Hradec Králové, Czech Republic.
Nucl Med Commun. 1996 Dec;17(12):1016-20. doi: 10.1097/00006231-199612000-00003.
The distribution and elimination of 99Tcm-complexes with methylene-diphosphonate (MDP) and with the calcium salt of diethylene-triamine-penta(methylene phosphonate) (DTPMP) were compared in rats. Both compounds exhibited high bone uptake and long-term retention of radioactivity in the skeleton. No significant accumulation of the complexes in non-osseous tissues was found. The pharmacokinetics of both chelates were similar, small differences in their distribution and elimination probably being due to different binding to plasma proteins. Two processes, namely bone uptake and kidney elimination, contributed to the disappearance of the complexes from the blood. The higher protein binding of 99Tcm-MDP probably caused its slower rate of urine elimination and insignificantly higher bone uptake compared with 99Tcm-DTPMP. On the other hand, the more rapid reduction in blood and muscle radioactivity with 99Tcm-DTPMP resulted in accelerated non-osseous tissue clearance compared with 99Tcm-MDP. This suggests that the time between administration and imaging may be shorter for 99Tcm-DTPMP than for 99Tcm-MDP. Furthermore, the much greater stability of 99Tcm-DTPMP may also reduce degradation of the complex and 99Tcm liberation in the body. For a general evaluation of both compounds, it will be necessary to determine lesion-to-bone ratios.
在大鼠体内比较了99锝标记的亚甲基二膦酸盐（MDP）复合物和二亚乙基三胺五（亚甲基膦酸盐）（DTPMP）钙盐复合物的分布与消除情况。两种化合物在骨骼中均表现出高摄取和放射性的长期滞留。未发现复合物在非骨组织中有明显蓄积。两种螯合物的药代动力学相似，其分布和消除的微小差异可能是由于与血浆蛋白的结合不同所致。骨摄取和肾脏排泄这两个过程导致了复合物从血液中消失。与99锝-DTPMP相比，99锝-MDP与蛋白质的结合力较高，这可能导致其尿液排泄速度较慢，骨摄取略高。另一方面，与99锝-MDP相比，99锝-DTPMP使血液和肌肉中的放射性更快降低，从而加速了非骨组织的清除。这表明99锝-DTPMP给药与成像之间的时间可能比99锝-MDP短。此外，99锝-DTPMP的稳定性高得多，这也可能减少复合物的降解和体内99锝的释放。为了对这两种化合物进行全面评估，有必要确定病变与骨的比值。
