19F/18F exchange synthesis for a novel [18F]S1P3-radiopharmaceutical

: Johanna Rokka, Cesare Federico, Jori Jurttila, Anniina Snellman, Merja Haaparanta, Juha O Rinne, Olof Solin

Publisher: WILEY-BLACKWELL

: 2013

: Journal of Labelled Compounds and Radiopharmaceuticals

: JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS

: J LABELLED COMPD RAD

: 8

: 56

: 8

: 385

: 391

: 7

: 0362-4803

DOI: https://doi.org/10.1002/jlcr.3055

F-19/F-18 isotope exchange is a useful method to label drug molecules containing F-19-fluorine with F-18 without modifying the drug molecule itself. Sphingosine-1-phosphate (S1P) is an important cellular mediator that functions by signaling through cell surface receptors. S1P is involved in several cell responses and may be related to many central nervous system disorders, including neural malfunction in Alzheimer's disease. In this study, [F-18]1-benzyl-N-(3,4-difluorobenzyl)-2-isopropyl-6-(2-methoxyethoxy)-1H-indole-3-carboxamide, a novel F-18-labeled positron emission tomography tracer for the S1P(3) receptor, was successfully synthesized using the F-19/F-18 isotope exchange reaction. Parameters of the reaction kinetics were studied, and correlations between the initial F-18-activity, the amount of precursor, radiochemical yield and specific activity (SA) were determined. Contrary to expectations, high initial F-18-activity decreased the radiochemical yield, and only a minor increase of SA occurred. F-19/F-18 exchange reaction is the use of 2 mu mol precursor with 20GBq of F-18-activity. F-18-activity and F-19/F-18 isotope exchange is used.