Complexation of lutetium-177 with bifunctional chelators in the presence of competing metals

金属元素存在下におけるLu-177と二官能性キレート剤との錯形成

渡辺 智; 橋本 和幸; 石岡 典子

Watanabe, Satoshi; Hashimoto, Kazuyuki; Ishioka, Noriko

As basic studies of bifunctional chelating agent for Lu -labeled antibodies, Lu complexation of DOTA and DTPA was investigated by the addition of competing metals, Ca(II), Fe(II) and Zn(II). From comparison of competing metals, the inhibition by competing metals on the Lu complexation was in the order of Ca(II)Fe(II)Zn(II) and Ca(II)Zn(II)Fe(II) as DOTA and DTPA, respectively. For comparison between DOTA and DTPA, the susceptibility to the inhibition on Lu complexation by all the three competing metals was DTPADOTA. Therefore, it was found that DTPA is advantageous for Lu complexation compared with DOTA in the presence of Ca(II), Fe(II) and Zn(II), and that the elimination of Fe from Lu solution is especially effective because the Lu complexation of DTPA is highly inhibited by Fe(II).