New preparation of [123I]PE2I:: investigation of the oxidation and purification steps

In order to simplify preparation of [I-123]PE2I, iodogen and hydrogen peroxide were examined as oxidants for the preparation of radioiodinated PE2I, e.g. (E)-N-(3-iodoprop-2-enyl)-2beta-carbomethoxy-3beta-(4'-tolyl) nortropane). Among the oxidizing compounds assayed, iodogen appears to afford the best results for this purpose (high radiochemical yield, high chemical purity and a reasonable reaction time). A simplified and efficient method is described here for the preparation of [I-123]PE2I based on the exchange of a I-123 tributyl tin analogue in oxidative conditions followed by purification by solid phase extraction (SPE). Using this method, [I-123]PE2I was obtained with a radiopharmaceutical yield over 60%, with chemical and radiochemical purities higher than 95% without the addition of a carrier ((NaI)-I-127) (2G Bq/nmol) or with a specific activity adjusted to 85-90 MBq/nmol in the presence of the carrier. Copyright (C) 2002 John Wiley Sons, Ltd.