Development of radium ion-selective macrocyclic chelating ligands for nuclear medicine treatment

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15206
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: Osaka University
• Principal Investigator: Nagata Kojiro 大阪大学, 放射線科学基盤機構附属ラジオアイソトープ総合センター, 助教 (10806871)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: キレート剤 / ラジウム / 安定度定数 / アルファ線 / バリウム / アクチニウム

Outline of Final Research Achievements

Two newly synthesised ligands were used to synthesise lanthanum complexes homologous to actinium and barium complexes homologous to radium for use in alpha-ray nuclear medicine therapy. With anionic ligands, the lanthanum complexes were found to have higher stability than the lanthanum complexes with known biological applications. In addition, actinium complexes were successfully synthesised at low ligand concentrations. On the other hand, the barium complexes were thermodynamically more stable than the lanthanum complexes when neutral ligands were used. This reversal of stability may be attributed to intramolecular interactions, and clarification of this cause will lead to the synthesis of stable radium complexes. In the future, complexes of cations with different ionic radii will also be synthesised and analysed in more detail.

Free Research Field

錯体化学、放射化学

Academic Significance and Societal Importance of the Research Achievements

本研究は不安定な錯体を与え易いラジウムやアクチニウムなどの巨大なカチオンを水中で安定に捕捉する分子の開発を行っている。このような巨大なカチオンの配位数や結合距離など錯体化学の分野でも未知の領域であり未解明な部分が多い。加えて、これらを安定に捕捉する手法を確立することができれば、アルファ線を放出する放射性同位元素を安全に投与でき、副作用の少ないがん治療法を世界に普及させることにも繋がると考えている。