Cyclodextrins (D. Duchêne (ed.): New Trends in Cyclodextrins and Derivatives (1991)) have long been shown to be capable of modifying the water solubility of a number of hydrophobic guests through the formation of inclusion complexes. Among the three natural cyclodextrins (α, β and γ-cyclodextrins containing 6, 7 and 8 d -glucopyranose units, respectively), β-cyclodextrin is by far the most commonly used although it exhibits a weaker solubility in water (and therefore a weaker solubilization power). This specific feature has encouraged the synthesis of derivatives exhibiting an increased solubility in water. Methylated cyclodextrins are amongst the simplest derivatives, and their properties regarding the solubility and the solubilization power for hydrophobic guests are well documented especially concerning Heptakis (2,6-di-Omethyl)-cyclodextrin (DIMEB) and Heptakis (2,3,6-tri-Omethyl)-cyclodextrin (TRIMEB) K. Koizumi et al .: J. Chromatogr . 368 , 329–337 (1986). In order to avoid the use of human serum albumin (HSA), this property has been applied here to the solubilization of a very sparingly water-soluble fatty acid derivative (16-iodo-3-methylhexadecanoic acid), which is known to localise in viable myocardial cells, allowing the generation of functional images reflecting the viability of the cardiac tissue through the use of radiolabeled analog (Demaison et al .: J. Nucl-Med . 29 , 1230–1236 (1998)). Nuclear magnetic resonance (NMR) was used throughout this study to evidence that the observed solubilization and stabilisation (under conditions required for sterilisation) induced by cyclodextrins are due to the formation of a true inclusion complex and not to non-specific interactions; This technique further allows to derive thermodynamic as well as structural informations for this complex. On one hand, the inclusion complex prevents thermal degradation during sterilisation process compared to HSA. On the other hand, NMR displacement experiments against HSA showed that the complex likely dissociates in vivo .

In order to visualize and quantify dopamine transporters, the synthesis of two novel ligands labelled with technetium-99m (Tc-99m) has been investigated. A multi-step synthesis afforded two target ligands with a tropane skeleton and a macrocyclic complexing moiety. The choice and the position of substituents are in adequation with dopamine transporter structure. The radiolabelling of these ligands with Tc-99m has been studied and the results make them good candidates for SPECT imaging. Copyright (C) 2002 John Wiley Sons, Ltd.

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.

A simplified and efficient method is described for the preparation of [123I]2-iodolisuride. The radioiodination of 3-(9,10-didehydro-6methyl-8a-ergolinyl)-1,1-diethylurea (lisuride) is based on tributyltin to 123I exchange in oxidative conditions. After optimization of the reaction parameters [123I]2-iodolisuride was obtained without high performance liquid chromatography purification with radiochemical yields >90% and a radiochemical purity higher than 95%. The specific activity of the product was more than 500 MBq/nmol. In vitro binding studies on striatal membranes and ex vivo autoradiography in rats showed that [123I] or [125I]2-iodolisuride prepared using this method, have the same radiopharmacological characteristics as radioiodinated iodolisuride prepared using the Iodogen® method.