Synthesis and in vitro evaluation of new translocator protein ligands designed for positron emission tomography.

Aim: Dysregulated levels of the translocator protein TSPO18KDa have been reported in several disorders, particularly neurodegenerative diseases. This makes TSPO an interesting target for the development of diagnostic biomarkers. Even though several radioligands have already been developed for in vivo TSPO imaging, the ideal TSPO radiotracer has still not been found. Results: Here, we report the chemical synthesis of a set of new TSPO ligands designed for future application in positron emission tomography, together with the determination of their biological activity and applied C-11-labeling strategy. Conclusion: The lead compound of our series, (R)-[C-11]Me@NEBIQUINIDE, showed very promising results and is therefore proposed to be further evaluated under in vivo settings.