Development and preparation of novel carbon-11/fluorine-18 containing radiotracers for non-invasive PET-imaging of EphB4

Abstract

Meeting Abstract Objectives: [11C]Choline has become an extensively used tracer in part due to its wide accessibility via simple and reliable synthetic protocols. The quality control for the tracer, however, seems still to be challenging. [11C]Choline is commonly synthesized by passing [11C]methyl iodide through a SPE cartridge wetted with 2- dimethylaminoethanol (DMEA), washing the cartridge with ethanol, water and eluting the product with saline. Thus the aim for chromatography is to separate sodium chloride, residual DMEA and [11C]choline for the reliable quantification DMEA, as it competes with [11C]choline in vivo. To achieve this, several chromatographic methods have been reported, e.g. RP with ion-pair elution and IC in different combinations with RI, conductivity or amperometric detection. The major difficulties listed were insufficient resolution and low detection sensitivity, which at times required two chromatographic runs to accomplish the task [1-4]. We investigated the capability of mixed-mode chromatography in resolving these issues.