2025-04-03 順天堂大学
順天堂大学などの研究チームは、宇宙空間の放射線環境下での医薬品の品質保持に関する研究を行い、全身麻酔薬プロポフォールが高速中性子線(1–5 MeV)を最大4Gy照射しても分子構造や品質にほとんど変化がないことを世界で初めて示しました。 一方、医薬品のガラス容器(バイアル)が中性子線照射により高い放射化を示すことも明らかになり、宇宙での医薬品保存における容器選定の重要性が浮き彫りとなりました。
◆この研究は、深宇宙での有人探査における医療体制構築の一環として行われ、宇宙放射線が医薬品に及ぼす影響を評価するための基礎的データを提供しています。 今後、宇宙用医薬品の放射線耐性データベース構築や、低放射化材料を用いた医薬品容器の開発など、宇宙環境下での医薬品の安定性確保と最適な管理手法の確立が期待されます。
<関連情報>
- https://www.juntendo.ac.jp/news/22451.html
- https://www.sciencedirect.com/science/article/pii/S2214552425000367
深宇宙類似環境における医薬品への中性子放射線の影響 – 宇宙における全身麻酔 – Effects of Neutron Radiation on Pharmaceuticals in Deep Space-like Environments – General Anesthesia in Space
Machiko Hatsuda, Masashi Hasegawa, Kimiaki Nakamura, Fumiyuki Yamakura, Tomohiro Kobayashi, Takaoki Takanashi, Yasuo Wakabayashi, Yoshie Otake, Toshio Naito, Hiroyuki Daida
Life Sciences in Space Research Available online 15 March 2025
DOI:https://doi.org/10.1016/j.lssr.2025.03.006
Graphical abstract
Highlights
- Evaluating the effects of space radiation on pharmaceuticals is an urgent issue in preparation for long-term stays and settlement on the Moon and Mars.
- The effects of secondary cosmic rays, including neutron radiation, are a concern within spacecraft and long-term storage containers.
- We propose evaluation methods of the effects of neutron radiation, generated as secondary radiation, on pharmaceuticals.
- We have shown that changes in the molecular structure of propofol are negligibly small under fast neutron irradiation with energies of 1-5 MeV at doses of 4 Gy or less.
- We have also observed significant activation of vials (glass containers) by neutrons, highlighting the risks associated with the containers.
Abstract
In deep space environments such as the Moon and Mars, secondary radiation generated by interactions between galactic cosmic rays and spacecraft walls or planetary surfaces presents a significant challenge. In particular, the effects of neutron radiation remain insufficiently understood. This study investigates the impact of neutron radiation on pharmaceuticals, specifically the general anesthetic propofol (2,6-Diisopropylphenol). Neutron irradiation experiments were conducted using the RIKEN Accelerator-driven Neutron Source (RANS), employing fast neutrons with energies of 1–5 MeV at doses up to 4 Gy. Analyses employing nuclear magnetic resonance (NMR), colorimetric assessment, micelle particle size measurement via optical microscopy, and high-performance liquid chromatography (HPLC) detected no discernible alterations in the molecular structure of propofol. Furthermore radiological activation analysis using Geiger-Müller (GM) counters and γ-ray spectral analysis with the germanium detector (Ge) indicated minimal radionuclide generation in the pharmaceutical itself, however significant activation was observed in glass vials. These findings highlight container activation as a critical risk factor in the storage and transportation of pharmaceuticals in space environments.
