| Autor: |
Sadahiro Naka, Tadashi Watabe, Thomas Lindner, Jens Cardinale, Kenta Kurimoto, Melissa Moore, Mitsuaki Tatsumi, Yuriko Mori, Eku Shimosegawa, Frank Valla, Hiroki Kato, Frederik L. Giesel |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
EJNMMI Radiopharmacy and Chemistry, Vol 6, Iss 1, Pp 1-12 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
2365-421X |
| DOI: |
10.1186/s41181-021-00142-z |
| Popis: |
Abstract Background Fibroblast activation protein (FAP) is overexpressed in the stroma of many types of cancer. [18F]AlF-FAPI-74 is a positron emission tomography tracer with high selectivity for FAP, which has already shown high accumulation within human tumors in clinical studies. However, [18F]AlF-FAPI-74 radiosynthesis has not been optimized using an automated synthesizer. Herein, we report a one-pot and one-step automated radiosynthesis method using a multi purpose synthesizer. Results Radiosynthesis of [18F]AlF-FAPI-74 was performed using a cassette-type multi purpose synthesizer CFN-MPS200. After the recovery rate of trapped [18F]fluoride onto the anion-exchange cartridge using a small amount of eluent was investigated manually, a dedicated [18F]AlF-FAPI-74 synthesis cassette and synthesis program for one-pot and one-step fluorination was developed. The solutions for the formulation of [18F]AlF-FAPI-74 synthesized using this were evaluated to obtain stable radiochemical purity. The recovery rate of [18F]fluoride with only 300 µL of eluent ranged 90 ± 9% by introduction from the male side and elution from the female side of the cartridge. In automated synthesis, the eluted [18F]fluoride and precursor solution containing aluminum chloride were mixed; then, fluorination was performed in a one-pot and one-step process at room temperature for 5 min, followed by 15 min at 95 °C. As a result, the radioactivity of [18F]AlF-FAPI-74 was 11.3 ± 1.1 GBq at the end of synthesis from 32 to 40 GBq of [18F]fluoride, and its radiochemical yield was 37 ± 4% (n = 10). The radiochemical purity at the end of the synthesis was ≥ 97% for all formulation solutions. When the diluent was saline, the radiochemical purity markedly decreased after 4 h of synthesis. In contrast, with phosphate-buffered saline (pH 7.4) or 10 mM phosphate-buffered saline (pH 6.7) containing 100 mg of sodium ascorbate, the radiochemical purity was stable at 97%. Non-radioactive AlF-FAPI-74 and total impurities, including non-radioactive AlF-FAPI-74, were 0.3 ± 0.1 µg/mL and 2.8 ± 0.6 µg/mL. Ethanol concentration and residual DMSO were 5.5 ± 0.2% and 21 ± 6 ppm, respectively. Conclusions We established a one-pot one-step automated synthesis method using a CFN-MPS200 synthesizer that provided high radioactivity and stable radiochemical purity for possible clinical applications. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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