Synthesis and characterization of a highly stable dendritic catechol-tripod bearing technetium-99m
作者:Annabelle Bertin、Anne-Isabelle Michou-Gallani、Jérôme Steibel、Jean-Louis Gallani、Delphine Felder-Flesch
DOI:10.1039/b9nj00305c
日期:——
The synthesis and preliminary biological tests (in vitro toxicity, in vitro stability) of new Tc(III)-radiolabelled dendro-chelates are presented. A dendritic 99mTc chelate 1 derived from a pre-organized tripodal tris-catecholamide exhibits a kinetic stability by far more important than its corresponding diethylenetriamine pentaacetic acid (DTPA) homologue 2. This permitted an assessment of the real impact of the pre-organized tripodal structure on kinetic inertness (and thus toxicity), an important issue to address when considering in vivo applications. Radiolabelling was performed using the stannous chloride reduction method; while DTPA-homologue 2 showed a high radiolabelling efficiency (96% radiolabelling yield after 30 min), tripodal complex 1 induced a 93% complexation yield after 45 min. In contrast, radiocomplex 1 derived from the most rigid and organized structure has a higher kinetic stability than 2. Indeed, while dissociation of 2 reached 50% after 1 h 30 min in physiological media like phosphate buffer saline (PBS) and bovine serum albumin (BSA), over 80% of 1 remained stable during the half-life of the radionucleide (6.02 h for 99mTc). Measurements of the cell leakage resulting from membrane damage of neuronal cells treated with increasing concentrations of dendritic ligand 16, together with pictures of treated neurons after staining, showed no detectable toxicity.
本文介绍了新型Tc(III)放射性标记树状螯合物的合成及初步生物测试(体外毒性、体外稳定性)。由预组织化的三足三酚胺衍生的树状99mTc螯合物1,其动力学稳定性远高于其对应的二乙烯三胺五乙酸(DTPA)同类物2。这使得能够评估预组织化三足结构对动力学惰性(因此对毒性)的真实影响,这是考虑体内应用时必须解决的重要问题。放射性标记是通过氯化锡还原法进行的;而DTPA同类物2在30分钟后显示出高达96%的放射性标记效率,三足复合物1在45分钟后诱导了93%的复合物形成率。相比之下,源自更刚性和有序结构的放射性复合物1展现出比2更高的动力学稳定性。实际上,在生理介质如磷酸盐缓冲盐水(PBS)和牛血清白蛋白(BSA)中,2在1小时30分钟后解离达50%,而超过80%的1在放射性核素的半衰期(99mTc为6.02小时)内保持稳定。对用不同浓度的树状配体16处理后的神经细胞膜损伤导致的细胞泄漏的测量,以及处理后的神经元染色后的图像,显示出未检测到毒性。