%0 Journal Article
%T Automatisation and First Evaluation of [18F]FE@SUPPY:2, an Alternative PET-Tracer for the Adenosine A3 Receptor: A Comparison with [18F]FE@SUPPY
%A Introduction:in vivoMethods:TRACERlab FxFNResults:Conclusion:
%J The Open Nuclear Medicine Journal
%D 2009
%I Bentham Open
%R 10.2174/1876388X00901010015]
%X Introduction: Since the Adenosine-A3-receptor was identified in the late 1990¡äs, there is little data available describing its distribution in vivo. Recently, we introduced [18F]FE@SUPPY as the first PET-tracer for this receptor. In the present investigation we translated this fluoroethyl-ester into the fluoroethyl-thioester [18F]FE@SUPPY:2 (5-ethyl 2,4-diethyl-3-((2-[18F]fluoroethyl) sulfanylcarbonyl)-6-phenylpyridine-5-carboxylate). Aims of the present study were the evaluation of (1) the automatized preparation of both [18F]FE@SUPPY-derivatives, (2) the biodistribution of [18F]FE@SUPPY:2, (3) the lipophilicity and (4) the comparison of the findings of [18F]FE@SUPPY and [18F]FE@SUPPY:2. Methods: The automated preparations of both [18F]FE@SUPPY-analogs were performed on a GE TRACERlab FxFN synthesizer using suitable precursors. Biodistribution experiments were performed using Sprague-Dawley rats/Him:OFA. Lipophilicity of the compounds was determined using an HPLC assay. Results: 22 automated radiosyntheses were performed for both radiotracers. Specific radioactivity was 70 ¡À 26GBq/¦Ìmol for [18F]FE@SUPPY and 340 ¡À 140GBq/¦Ìmol for [18F]FE@SUPPY:2. Biodistribution experiments evinced bowels and liver as organs with highest uptake and intermediate uptake in kidney, lung and heart. LogP values of both molecules ranged from 3.99 to 4.12 at different pH. Conclusion: From a radiopharmaceutical perspective, drastically better specific radioactivities would militate in favour of [18F]FE@SUPPY:2; preclinical evaluations, so far, do not permit the decision upon the selection of the optimum [18F]FE@SUPPY-derivative. With [18F]FE@SUPPY:2, we are able to provide a second potential tracer that could help to further characterize the still quite unexplored Adenosine-A3-receptor.
%U http://www.benthamscience.com/open/tonmedj/article/V001/15TONMEDJ.htm