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Pittsburgh compound B ([11C]PiB) is the gold standard positron emission tomography (PET) tracer for the in vivo imaging of amyloid plaques. Currently, it is synthesized by either solution chemistry or using a 'dry loop' approach followed by HPLC purification within 30 minutes starting from [11C]CO2. Here, we report a novel, highly efficient solid phase supported carbon-11 radiolabeling procedure using commercially available disposable tC18 cartridge as a '3-in-1' entity: reactor, purifier, and solvent replacement system. [11C]PiB is synthesized by passing gaseous [11C]CH3OTf through a tC18 cartridge preloaded with a solution of precursor. Successive elution with aqueous ethanol solutions allows for nearly quantitative separation of the reaction mixture to provide chemically and radiochemically pure PET tracer. [11C]PiB suitable for human injection is produced within 10 minutes starting from [11C]CH3OTf (20 min from [11C]CO2) in 22% isolated yield not corrected for decay and molar activity of 190 GBq/μmol using 0.2 mg of precursor. This technique reduces the amount of precursor and other supplies, avoids use of preparative HPLC and toxic solvents, and decreases the time between consecutive production batches. Solid phase supported technique can facilitate [11C]PiB production compliant with Good Manufacturing Practice (GMP) and improve synthesis reliability. [ABSTRACT FROM AUTHOR]

Changes in expression and dysfunctional signaling of TrkA/B/C receptors and oncogenic Trk fusion proteins are found in neurological diseases and cancers. Here, we describe the development of a first 18 F-labeled optimized lead suitable for in vivo imaging of Trk, [ 18 F]TRACK, which is radiosynthesized with ease from a nonactivated aryl precursor concurrently combining largely reduced P-gp liability and improved brain kinetics compared to previous leads while displaying high on-target affinity and human kinome selectivity.