Radiosynthesis of racemic and enantiomerically pure (-)-[18F]flubatine--a promising PET radiotracer for neuroimaging of α4β2 nicotinic acetylcholine receptors

Appl Radiat Isot. 2013 Apr:74:128-36. doi: 10.1016/j.apradiso.2013.01.002. Epub 2013 Jan 11.

Abstract

(-)-[(18)F]flubatine is a promising agent for visualization by PET of cerebral α4β2 nicotinic acetylcholine receptors (nAChRs), which are implicated in psychiatric and neurodegenerative disorders. Here, we describe a substantially improved two-step radiosynthesis strategy for (-)-[(18)F]flubatine, based on the nucleophilic radiofluorination of an enantiomerically pure precursor followed by deprotection of the intermediate. An extensive leaving group/protecting group library of precursors was tested. Application of a trimethylammonium-iodide precursor with a Boc-protecting group provided the best results: labeling efficiencies of 80-95%, RCY of 60±5%, radiochemical purity of >98%, and a specific activity of >350GBq/μmol. The radiosynthesis is easily transferable to an automated synthesis module.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Benzamides / chemical synthesis*
  • Benzamides / chemistry
  • Brain / diagnostic imaging
  • Brain / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic / chemical synthesis*
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry
  • Chemistry Techniques, Synthetic
  • Fluorine Radioisotopes / chemistry*
  • Humans
  • Positron-Emission Tomography
  • Radiopharmaceuticals / chemical synthesis*
  • Radiopharmaceuticals / chemistry
  • Receptors, Nicotinic / metabolism*
  • Stereoisomerism

Substances

  • Benzamides
  • Bridged Bicyclo Compounds, Heterocyclic
  • Fluorine Radioisotopes
  • Radiopharmaceuticals
  • Receptors, Nicotinic
  • fluoronorchloroepibatidine
  • nicotinic receptor alpha4beta2