Radiosynthesis and in-vivo evaluation of [125I]IBT: a single-photon emission computed tomography radiotracer for α7-nicotinic acetylcholine receptor imaging

Nucl Med Commun. 2017 Aug;38(8):683-693. doi: 10.1097/MNM.0000000000000700.

Abstract

Aim: The aim of this study was to develop several novel α7-nicotinic acetylcholine receptor (nAChR) radioligands for the early diagnosis and treatment of Alzheimer's disease.

Patients and methods: The study reported six compounds and studied the in-vitro receptor binding affinity, and selected the I-labeled IBT with good characteristics as a novel radioligand suitable for studying α7-nAChRs. After verifying the stability of the radiotracer [I]IBT, the biodistribution in vivo and regional brain biodistribution studies were carried out in mice. Blocking studies with methyllycaconitine citrate and nicotine were carried out under control and blocking conditions, and the metabolic stability was assessed in vivo in the plasma, brain, and liver.

Results and conclusion: The results of our study suggested that [I]IBT had affinity for α7-nAChRs. The in-vivo evaluation in mice of [I]IBT showed a high brain/blood ratio and excellent metabolic stability. The regional brain distribution studies and the blocking studies showed that it had favorable selectivity and specificity and was a potential α7-nAChRs radioligand.

MeSH terms

  • Animals
  • Chemistry Techniques, Synthetic
  • Drug Stability
  • Female
  • Hydrophobic and Hydrophilic Interactions
  • Mice
  • Radioactive Tracers
  • Radiochemistry
  • Radiopharmaceuticals / chemical synthesis*
  • Radiopharmaceuticals / chemistry*
  • Radiopharmaceuticals / metabolism
  • Radiopharmaceuticals / pharmacokinetics
  • Rats
  • Tissue Distribution
  • Tomography, Emission-Computed, Single-Photon / methods*
  • alpha7 Nicotinic Acetylcholine Receptor / metabolism*

Substances

  • Radioactive Tracers
  • Radiopharmaceuticals
  • alpha7 Nicotinic Acetylcholine Receptor