Preparation of the metabotropic glutamate receptor 5 (mGluR5) PET tracer [(18)F]FPEB for human use: An automated radiosynthesis and a novel one-pot synthesis of its radiolabeling precursor.

The radiotracer 3-[(18)F]fluoro-5-(2-pyridinylethynyl)benzonitrile, or [(18)F]FPEB, is a promising PET imaging agent for the metabotropic glutamate subtype 5 receptor (mGluR5). In an effort to develop a routine production method of this radiotracer for use in clinical research we adapted its radiosynthesis to an automated chemistry module. In the meanwhile, we also developed a simplified "one-pot" method for the preparation of the nitrobenzonitrile radiolabeling precursor for [(18)F]FPEB and its reference standard to replace the existing multi-step synthetic approach.