Preparation and stability of ethanol-free solution of [18F]florbetapir ([18F]AV-45) for positron emission tomography amyloid imaging

• Published in: Journal of labelled compounds & radiopharmaceuticals 2013-05, Vol.56 (5), p.295-300
• Main Authors: Hayashi, Kazutaka, Tachibana, Akiko, Tazawa, Shusaku, Mizukawa, Yosuke, Osaki, Katsuhiko, Morimoto, Yoko, Zochi, Riyo, Kurahashi, Masahiro, Aki, Hatsumi, Takahashi, Kazuhiro
• Format: Article
• Language: English
• Subjects: [18F]AV-45; Alzheimer's disease; Aniline Compounds - chemical synthesis; Aniline Compounds - chemistry; automated synthesis; disposable components; Ethylene Glycols - chemical synthesis; Ethylene Glycols - chemistry; Isotope Labeling - methods; Radiopharmaceuticals - chemical synthesis; Radiopharmaceuticals - chemistry; β-amyloid
• ISSN: 0362-4803; 1099-1344
• DOI: 10.1002/jlcr.3021

We have developed an ethanol‐free formulation method of [18F]florbetapir ([18F]AV‐45) using a commercially available automated JFE multi‐purpose synthesizer. We have also evaluated the radiochemical stability in an ethanol‐free solution of [18F]AV‐45 under visible light irradiation and dark conditions by comparison with a conventional 10% ethanol solution of [18F]AV‐45. [18F]AV‐45 was obtained with a radiochemical yield of 55.1 ± 2.2% (decay‐corrected to end of bombardment), specific activity of 591.6 ± 90.3 GBq/µmol and radiochemical purity of >99% within a total synthesis time of about 73 min. The radiochemical purity of [18F]AV‐45 formulated by dissolving the ethanol‐free solution was found to decrease as a function of the period of exposure to visible light. In contrast, the visible light photolysis could be suppressed by adding 10% ethanol to the formulation or by avoiding exposure to visible light. In the radiosynthesis of [18F]AV‐45 formulated by dissolving the ethanol‐free solution, [18F]AV‐45 could be obtained with high radiochemical purity and high stability by avoiding exposure to visible light. Copyright © 2013 John Wiley & Sons, Ltd. We have developed an ethanol‐free formulation method of [18F]florbetapir ([18F]AV‐45) using a commercially available synthesizer. We have also evaluated the radiochemical stability in an ethanol‐free solution of [18F]AV‐45 under visible light irradiation and dark conditions by comparison with a conventional 10% ethanol solution of [18F]AV‐45. The radiochemical purity of [18F]AV‐45 formulated by dissolving the ethanol‐free solution was found to decrease as a function of the period of exposure to visible light. In contrast, the visible light photolysis could be suppressed by adding 10% ethanol to the formulation or by avoiding exposure to visible light. In the radiosynthesis of [18F]AV‐45 formulated by dissolving the ethanol‐free solution, [18F]AV‐45 could be obtained with high radiochemical purity and high stability by avoiding exposure to visible light.