Preparation of fluorine-18-labelled fluoromisonidazole using two different synthesis methods

✍ Scribed by Eeva-Liisa Kämäräinen; Teija Kyllönen; Outi Nihtilä; Heikki Björk; Olof Solin

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: French
• Weight: 112 KB
• Volume: 47
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.795

✦ Synopsis

Abstract

^18^F‐labelled fluoromisonidazole [1H‐1‐(3‐[^18^F]fluoro‐2‐hydroxypropyl)‐2‐nitroimida‐zole; ([^18^F]FMISO)] is used as an in vivo marker of hypoxic cells in tumours and ischaemic areas of the heart and the brain. The compound plays an important role in evaluating the oxygenation status in tumours during radiotherapy. In this paper, we report experiments carried out in our laboratory in synthesizing [^18^F]FMISO using two different methods. The first method (I) for the [^18^F]FMISO synthesis was the fluorination of (2R)‐(−)‐glycidyl tosylate to [^18^F]epifluorohydrin. The subsequent nucleophilic ring opening, achieved with 2‐nitroimidazole, leads to labelled FMISO. The second method (II) was the fluorination of the protected precursor 1‐(2′‐nitro‐1′‐imidazolyl)‐2‐O‐tetrahydropyranyl‐3‐O‐toluenesulphonyl‐propanediol, followed by a rapid removal of the protecting group. With the first method, the radiochemical yield was about 10% at the end of the synthesis (EOS), and the radiochemical purity was over 99%. The radiochemical yield in the second method was 21% (EOS) on an average, and the radiochemical purity was over 97%. When an automated commercial synthesis module was used with method II, slightly better and more reproducible yields were achieved. The improvement in the synthesis yield with the automated apparatus will be valuable when working with high activities, and therefore it is under further development. Copyright © 2003 John Wiley & Sons, Ltd.