Lead(II) complexes of 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate: Solution chemistry and application to tumor localization with Pb-203 labeled monoclonal antibodies
Lead(II) complexes of 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate: Solution chemistry and application to tumor localization with Pb-203 labeled monoclonal antibodies
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DOI：
10.1016/0020-1693(95)04708-5
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发表时间：
1995-11-01
影响因子：
2.8
通讯作者：
Gansow, OA
中科院分区：
文献类型：
--
作者：
Pippin, CG;McMurry, TJ;Gansow, OA
The aqueous solution chemistry of lead(II) complexes of DOTA (DOTA(4-)=1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate) has been investigated in the course of developing Pb-203 radiolabeled monoclonal antibodies as imaging agents. The stability and protonation constant of the 1:1 complex of Pb(DOTA)(2-) were estimated to be 10(24.3+/-0.2) and 10(3.3+/-0.1) at 25 degrees C, I=0.10 M (NaClO4), respectively. Formation reaction kinetics between Pb(II) and DOTA were investigated by stopped-flow methods. Possible mechanisms developed for the reaction involve (i) the rapid formation of a protonated intermediate which subsequently loses a proton during the rate-limiting step and (ii) formation of a rapid 'dead-end' equilibrium, with reactants reacting by a second-order process to give products. Dissociation of Pb(DOTA)(2-) to form the aquo Pb(II) cation and protonated DOTA was studied in perchloric acid. These results, when applied to the radiolabeling of monoclonal antibody B72.3 conjugates of DOTA with Pb-203, led to, the biological evaluation of the Pb-203(DOTA)-B72.3 radioimmunoconjugate in mice, Biodistribution studies reported here suggest that Pb-203(DOTA) labeled monoclonal antibodies may be useful for tumor localization of Pb(II) radionuclides.
