Bartoś Barbara, Lyczko Krzysztof, Kasperek Agata, Krajewski Seweryn, Bilewicz Aleksander
Centre for Radiochemistry and Nuclear Chemistry, Institute of Nuclear Chemistry and Technology, Dorodna 16 03-195, Warszawa, Poland.
J Radioanal Nucl Chem. 2013;295(1):205-209. doi: 10.1007/s10967-012-2238-4. Epub 2012 Sep 19.
The short half-life of Bi and Bi limits the application of these radionuclides in α radionuclide therapy. The labeling of biomolecules with Pb (mother nuclide of Bi) instead of Bi or Bi has the advantage of obtaining a conjugate with a half-life of 10.6 h, compared with of 60 min for Bi or 46 min for Bi. Previous attempts to prepare a potential in vivo generator with Pb complexed by the DOTA chelator failed, because about 36 % of Bi was reported to escape as a result of the radioactive decay [Formula: see text]. Herein, we report studies on the stability of the Pb complexes with eight selected polydentate ligands, which demonstrate high affinity for 3+ metal cations. From the ligand studied DOTP and BAPTA show a sufficient Pb labeling yields but only Pb-DOTP complex is stable in isotonic solution of sodium chloride making this way radioactivity level of released Bi is below the limit of detection. It should be emphasized that the DOTP complex is stable only in the case when the concentration of free DOTP exceeds 10 M.
铋-212和铋-213的短半衰期限制了这些放射性核素在α放射性核素治疗中的应用。用铅（铋-212的母核素）而非铋-212或铋-213标记生物分子的优势在于可获得半衰期为10.6小时的缀合物，相比之下，铋-212的半衰期为60分钟，铋-213的半衰期为46分钟。此前尝试制备由DOTA螯合剂络合铅的潜在体内发生器的努力失败了，因为据报道约36%的铋-212会因放射性衰变而逸出[公式：见原文]。在此，我们报告了对铅与八种选定多齿配体形成的络合物稳定性的研究，这些配体对3 +金属阳离子显示出高亲和力。在所研究的配体中，二乙基三胺五乙酸（DOTP）和1,2 -双（2 -氨基苯氧基）乙烷 - N,N,N',N'-四乙酸（BAPTA）显示出足够的铅标记产率，但只有铅 - DOTP络合物在氯化钠等渗溶液中稳定，使得释放的铋-212的放射性水平低于检测限。应当强调的是，只有当游离DOTP的浓度超过10 M时，DOTP络合物才稳定。
