Preparation of a bromine-76 labelled analogue of epibatidine: a potent ligand for nicotinic acetylcholine receptor studies

• Published in: Applied radiation and isotopes 2002-11, Vol.57 (5), p.713-717
• Main Authors: Kassiou, M, Loc’h, C, Dolle, F, Musachio, J.L, Dolci, L, Crouzel, C, Dannals, R.F, Mazière, B
• Format: Article
• Language: English
• Subjects: Animals; Bridged Bicyclo Compounds, Heterocyclic - chemical synthesis; Bridged Bicyclo Compounds, Heterocyclic - chemistry; Bridged Bicyclo Compounds, Heterocyclic - metabolism; Bromine Radioisotopes - isolation & purification; Bromine-76; Epibatidine; In Vitro Techniques; Ligands; Nicotinic acetylcholine receptors; PET; Pyridines - chemical synthesis; Pyridines - chemistry; Pyridines - metabolism; Radiochemistry; Radiopharmaceuticals - chemical synthesis; Radiopharmaceuticals - chemistry; Radiopharmaceuticals - metabolism; Receptors, Nicotinic - metabolism; Tomography, Emission-Computed
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/S0969-8043(02)00187-2

Epibatidine analogues have been labelled with I-123 for single photon emission computed tomography and with short half-life positron emitters (C-11 and F-18) for PET. For easier radiopharmacological studies the bromo analogue of epibatidine (norchlorobromoepibatidine or exo-7-azabicyclo-2-(2-bromo-5-pyridyl)-[2.2.1]heptane) was labelled with Br-76, a longer half-life positron emitter, ( T 1/2=16.2 h). [ 76Br]-norchlorobromoepibatidine was prepared by using a Cu + assisted bromodeiodination exchange from the iodo analogue in reducing conditions at 190°C. The tracer purified by RP-HPLC was obtained in 70% radiochemical yield with a specific radioactivity of 20 GBq/μmol. Radiochemical and chemical purities measured by radio-TLC and HPLC were >98%.