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A new automated radiosynthesis of [11C]2‐(2,6‐difluoro‐4‐((2‐(N‐methylphenylsulfonamido)ethyl)thio)phenoxy)acetamide ([11C]K2), a radiopharmaceutical for the glutamate α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) receptor, is reported. Although manual syntheses have been described, these are unsuitable for routine production of larger batches of [11C]K2 for (pre)clinical PET imaging applications. To meet demands for the imaging agent from our functional neuroimaging collaborators, herein, we report a current good manufacturing practice (cGMP)‐compliant synthesis of [11C]K2 using a commercial synthesis module. The new synthesis is fully automated and has been validated for clinical use. The total synthesis time is 33 min from end of bombardment, and the production method provides 2.66 ± 0.3 GBq (71.9 ± 8.6 mCi) of [11C]K2 in 97.7 ± 0.5% radiochemical purity and 754.1 ± 231.5 TBq/mmol (20,382.7 ± 6256.1 Ci/mmol) molar activity (n = 3). Batches passed all requisite quality control testing confirming suitability for clinical use. [ABSTRACT FROM AUTHOR]

An in‐loop 11C‐carbonylation process for the radiosynthesis of 11C‐carboxylic acids and esters from halide precursors has been developed. The reaction proceeds at room temperature under mild conditions and enables 11C‐carbonylation of both electron deficient and electron rich (hetero)aromatic halides to provide 11C‐carboxylic acids and esters in good to excellent radiochemical yields, high radiochemical purity, and excellent molar activity. The process has been fully automated using commercial radiochemistry synthesis modules, and application to clinical production is demonstrated via validated cGMP radiosyntheses of [11C]bexarotene and [11C]acetoacetic acid. [ABSTRACT FROM AUTHOR]

[11C]Verubulin (a.k.a.[11C]MCP-6827), [11C]HD-800 and [11C]colchicine have been developed for imaging microtubules (MTs) with positron emission tomography (PET). The objective of this work was to conduct an in vivo comparison of [11C]verubulin for MT imaging in mouse and rat brain, as well as an in vitro study with this radiotracer in rodent and human Alzheimer's Disease tissue. Our preliminary PET imaging studies of [11C]verubulin in rodents revealed contradictory results between mouse and rat brain uptake under pretreatment conditions. In vitro autoradiography with [11C]verubulin showed an unexpected higher uptake in AD patient tissue compared with healthy controls. We also conducted the first comparative in vivo PET imaging study with [11C]verubulin, [11C]HD-800 and [11C]colchicine in a non-human primate. [11C]Verubulin and [11C]HD-800 require pharmacokinetic modeling and quantification studies to understand the role of how these radiotracers bind to MTs before translation to human use. [ABSTRACT FROM AUTHOR]

A new variant of the Strecker synthesis using no-carrier-added [11C]cyanide for the synthesis of radiolabeled amino acids is described. The protocol is fully automated using a radiochemistry synthesis module and applied to the production of a number of new PET radiotracers. [11C-Carbonyl]sarcosine, [11C-carbonyl]methionine, [11Ccarbonyl]- N-phenylglycine, and [11C-carbonyl]glycine are all synthesized in moderate to good radiochemical yields. The synthesis of [11C-carbonyl] sarcosine has been validated for production of doses for clinical use, and preliminary evaluation of the new radiotracer in PC3 tumor-bearing mice is also reported. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) imaging of Colony Stimulating Factor 1 Receptor (CSF1R) is a new strategy for quantifying both neuroinflammation and inflammation in the periphery since CSF1R is expressed on microglia and macrophages. AZ683 has high affinity for CSF1R (Ki = 8 nM; IC50 = 6 nM) and >250-fold selectivity over 95 other kinases. In this paper, we report the radiosynthesis of [11C]AZ683 and initial evaluation of its use in CSF1R PET. [11C]AZ683 was synthesized by 11C-methylation of the desmethyl precursor with [11C]MeOTf in 3.0% non-corrected activity yield (based upon [11C]MeOTf), >99% radiochemical purity and high molar activity. Preliminary PET imaging with [11C]AZ683 revealed low brain uptake in rodents and nonhuman primates, suggesting that imaging neuroinflammation could be challenging but that the radiopharmaceutical could still be useful for peripheral imaging of inflammation. [ABSTRACT FROM AUTHOR]