Pharmaceuticals (Dec 2018)

Synthesis and Initial In Vivo Evaluation of [<sup>11</sup>C]AZ683—A Novel PET Radiotracer for Colony Stimulating Factor 1 Receptor (CSF1R)

  • Sean S. Tanzey,
  • Xia Shao,
  • Jenelle Stauff,
  • Janna Arteaga,
  • Phillip Sherman,
  • Peter J. H. Scott,
  • Andrew V. Mossine

DOI
https://doi.org/10.3390/ph11040136
Journal volume & issue
Vol. 11, no. 4
p. 136

Abstract

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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.

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