Abstract

Lab-on-a-chip Devices for Synthesis and Quality Control of Positron Emission Tomography Radiopharmaceuticals

Steve Archibald, Professor, University Of Hull

Modules for electrode trapping and release of [18F]fluoride, synthesis of [18F]FDG and purification have been produced as prototypes using bespoke manufactured microfluidic glass chips with etched channels. A key component of the synthesis system is the monolithic separation column which were made from silica and chemically modified for the purification and separation applications. Synthesis to validate the [18F]fluoride feed was carried out in a heated capillary loop. Spectroscopic quality control tests were developed using a simple on-chip absorbance-based system to allow quality control tests to be performed rapidly (few min) with small volumes (<2 µL). A process for highly efficient trap and release of [18F]fluoride from a low volume (< 200 µl) of aqueous solution allows trap and release into acetonitrile with an efficiency of up to 95% in both steps. Modules were designed and tested for the synthesis of [18F]FDG as well as other fluorine-18 and gallium-68 containing radiopharmaceuticals. The efficient process for transfer of the [18F]fluoride into acetonitrile via electrode trapping allows synthesis of the radiotracers in high yield at low solvent volumes. Separation modules using small (1-2 cm length) bespoke monolithic silica columns were validated and some of the quality control tests were shown to be effective using both real samples and standards.