Creation of a radiolabeling method that enables the development of Therapeutic Radiopharmaceuticals using the alpha-emitting nuclide Ra-223

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K17204
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Yokohama City University
• Principal Investigator: TAKADA Yuuki 横浜市立大学, 医学研究科, 特任助教 (50348463)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: ラジウム-233 / α線放出RI内用療法薬 / アニオン性フタロシアニン / レーキ

Outline of Final Research Achievements

In this study, three of nine commercially available anionic phthalocyanines,　such as phthalocyanine tetrasulfonic acid (FreeTSPc) and copper phthalocyanine tetrasulfonic acid (CuTSPc) had been selected by no water-soluble compounds were found in the supernatant after preparation of lake pigments with barium.　As using 133BaCl2 solution, Ba-133 lake pigments were obtained with a labeling yield of 50-60%.　Furthermore, 133BaCl2 solution was directly added to powder of FreeTSPc or CuTSPc, and after heating to dryness, the labeling yield of Ba-133 lake pigments has been improved to 75-95%.
We gained a foothold for the development of therapeutic radiopharmaceuticals using the alpha-emitting nuclide Ra-233.

Free Research Field

放射性医薬品学

Academic Significance and Societal Importance of the Research Achievements

Ra-233を用いたα線放出RI内用療法薬はゾーフィゴ（223RaCl2）が唯一承認されているのみで他のRa-233標識化合物は実用に至っていない。本研究では、Ra-233および同じアルカリ土類金属のBa-133を用いてフタロシアニンテトラスルホン酸類に対して標識（レーキの作成）を試み、Ba-133をバリウムレーキとして封じ込めることに成功した。
本研究により、Ra-233を用いたα線放出RI内用療法薬の開発のための足掛かりを得ることができた。