The preparation of123/125I-clioquinol for the study of Aβ protein in Alzheimer's disease

Abstract

Clioquinol or 5-chloro-7-iodo-8-hydroxyquinoline (CQ) is a lipophilic hydroxyquinoline currently under investigation for the treatment of Alzheimer's disease by targeted copper and zinc chelation. CQ was radiolabelled with no-carrier-added iodine-123/125 to give high specific activity analogs for SPECT imaging and biochemical studies. 123I-clioquinol ( 123I-CQ) was prepared by direct iodination of the activated hydroxyquinoline using a variety of oxidants. Highest yields (>85%) and purity were obtained when chloramine-T or iodogen at pH 4-5 was used. Large-scale radiolabelled 123I-CQ was purified by reverse-phase HPLC using a C-18 small 'Rocket®' column. The radiochemical purity of 123I-CQ a..