Routine quality control of recycled target [18O]water by capillary electrophoresis and gas chromatography

Convenient recycling and reuse of bombarded [¹⁸O]H₂O for the production and the application of [¹⁸F]F⁻

The limited availability and the increasing demands of [(18)O]H2O force the reuse of bombarded [(18)O]H2O for the production of [(18)F]F(-) at least for the purposes of research. Therefore, inorganic and organic contaminants have to be removed from the [(18)O]H2O after bombardment. We present a simple, effective, easy-handling and reliable method of [(18)O]H2O purification including oxidation and distillation. The obtained recycled [(18)O]H2O had comparable quality to commercially distributed [(18)O]water. This was confirmed by a detailed comparison of produced radionuclides and their activities and the application of [(18)F]F(-) for the automated synthesis of [(18)F]fluspidine.

Purification by ozonolysis of 18O enriched water after cyclotron irradiation and the utilization of the purified water for the production of [18F]-FDG (2-deoxy-2-[18F]-fluoro-d-glucose)

The high cost of virgin (18)O-enriched water has forced many researchers to study methods to purify and recycle enriched water after the first irradiation for the production of radiopharmaceuticals. In our study, [(18)O]H(2)O was purified by ozonolysis and distillation. Analyses showed a large decrease in impurities after this treatment. The purification procedure was carried out after the production of 94 batches of [18F]-FDG, which were manufactured using a GE Minitrace cyclotron and a GE Mx TracerLab synthesizer. Saturation yields after bombardment, using virgin and re-purified water were, respectively, 2864+/-204MBq/muA and 2727+/-167MBq/muA, a decrease of 5.5%. The decrease in [18F]-FDG yield, from 67.2+/-0.7% to 65.5+/-0.9%, can be ascribed to the irradiation step only.

Simple purification of recovered [18O]H2O by UV, ozone, and solid-phase extraction methods

We have developed three methods for removing organic impurities as well as a solid-phase extraction (SPE) method for removing metallic and ionic impurities from recovered [18O]H2O. Preliminary experiments with [16O]H2O were used to determine the optimal purification conditions. These showed that UV irradiation rapidly (<4 h) eliminated low boiling point impurities such as acetonitrile and acetone with only a slight loss of mass. A combination of UV irradiation and purging with ozone removed high boiling point impurities such as ethanol and methanol more quickly than UV irradiation alone. UV irradiation followed by a SPE with [18O]H2O removed all organic and inorganic impurities. The purified [18O]H2O gave a saturation yield of 128.62+/-15.6 mCi/microA for [18F]fluoride and a 49.8+/-12.7% radiochemical yield for [18F]fluorodeoxyglucose.