RT Journal Article SR Electronic T1 Development of a 18F labeled acetylcholinesterase ligand as tracer as a radiopharmaceutical for diagnosis of Alzheimer`s disease. JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1550 OP 1550 VO 56 IS supplement 3 A1 Fernandez, Soledad A1 Giglio, Javier A1 Reyes, Laura A1 Oliver, Patricia A1 González, Mercedes A1 Engler, Henry A1 Rey, Ana A1 Cerecetto, Hugo YR 2015 UL http://jnm.snmjournals.org/content/56/supplement_3/1550.abstract AB 1550 Objectives Acetylcholinesterase (AChE) is a valuable CNS PET imaging target. The aim of this work is to develop a potential 18F labelled radiopharmaceutical as marker of the activity of acetylcholinesterase (AChE) in Alzheimer`s disease (AD).Methods New AChE inhibitors were identified in vitro and compound 3-(benzyloxy)-1-(5-bromopentyl)-5-nitro-1H-indazole (IND) was selected for labeling. Labeling was performed by substitution of the Br in the IND by 18F for obtaining [18F]IND. The precursor, dissolved in DMSO was treated with K18F in presence of Kryptofix-222 in the nucleophilic synthesis module Tracerlab FXFN GE. The radiochemical purity was assessed by means of HPLC (the method was optimized). Bio-distribution studies were conducted in normal animals (Swiss female 2-month-old mice).Results The best results were obtained in conditions 2 (see Table 1). The labelled compound was obtained with a yield of 25.0±5.5%(n = 5) (not decay corrected (NCD)) and radiochemical purity of 98.3±0.3%, (n=5). Residual solvents are below in the USP defined limit. The distribution in normal animals revealed the characteristic profile of a highly lipophilic compound, high hepatobiliar elimination (22.6 ± 0.3 after 30 minutes, n=3) and low urinary excretion (12.4 ± 3.5 30 minutes, n=3). The compound crossed the blood brain barrier (BBB ) and a uptake in the brain of 3.5 ± 0.3 % Administrated activity/gram (n=3) was observed at 30 minutes post-injection.Conclusions [18F]IND cross the BBB and might be an interesting radioligand for in vivo comparative studies of the AChE brain activity in health animals and animals with AD.Research Support Acknowledgements: ANII; PEDECIBA - Química; Proyecto CSIC(España)-UdelaR(Uruguay) Table 1 - Optimization the parameters of synthesis