Synthesis of [¹¹C]PBR170, a novel imidazopyridine, for imaging the translocator protein with PET

Appl Radiat Isot. 2014 Aug:90:46-52. doi: 10.1016/j.apradiso.2014.03.009. Epub 2014 Mar 18.

Abstract

The translocator protein (TSPO) ligand 2-(6,8-dichloro-2-(4-ethoxyphenyl)imidazo[1,2-a]pyridin-3-yl)-N-(2-fluoropyridin-3-yl)-N-methylacetamide (PBR170), is a novel imidazopyridineacetamide with high affinity (2.6 nm) and selectivity for the TSPO. The synthesis of [(11)C]PBR170 was accomplished by N-methylation of the corresponding desmethyl precursor with [(11)C]methyl iodide in the presence of sodium hydroxide in dimethylformamide. [(11)C]PBR170 was produced in 30-45% radiochemical yield (decay-corrected, based on [(11)C]methyl iodide) with a radiochemical purity >98% and a specific activity of 90-190 GBq/μmol after 35 min of synthesis time.

Keywords: Carbon-11; PET; TSPO; [(11)C]PBR170; [(11)C]methyl iodide.

MeSH terms

  • Animals
  • Carbon Radioisotopes / chemistry
  • Carbon Radioisotopes / pharmacokinetics
  • Isotope Labeling / methods
  • Molecular Imaging / methods*
  • Organ Specificity
  • Positron-Emission Tomography / methods*
  • Protein Binding
  • Pyridines / chemical synthesis*
  • Pyridines / pharmacokinetics*
  • Radiopharmaceuticals / chemical synthesis
  • Radiopharmaceuticals / pharmacokinetics
  • Rats
  • Rats, Wistar
  • Receptors, GABA / metabolism*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Tissue Distribution

Substances

  • Carbon Radioisotopes
  • Pyridines
  • Radiopharmaceuticals
  • Receptors, GABA
  • TSPO protein, human