Radiosynthesis And In-Vivo Evaluation Of [I-125]Ibt: A Single-Photon Emission Computed Tomography Radiotracer For 7-Nicotinic Acetylcholine Receptor Imaging

AimThe aim of this study was to develop several novel 7-nicotinic acetylcholine receptor (nAChR) radioligands for the early diagnosis and treatment of Alzheimer's disease.Patients and methodsThe study reported six compounds and studied the in-vitro receptor binding affinity, and selected the I-125-labeled IBT with good characteristics as a novel radioligand suitable for studying 7-nAChRs. After verifying the stability of the radiotracer [I-125]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 conclusionThe results of our study suggested that [I-125]IBT had affinity for 7-nAChRs. The in-vivo evaluation in mice of [I-125]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 7-nAChRs radioligand.