TAT-10: Exploration of the Chemistry of Astatine; From Basic Research Towards Applied Questions

Kanazawa, Japan (UroToday.com) Conventional As211 labeling protocols are based on astatine as an iodine analog. These are lacking since astatbenzoate-labeled compounds are unstable when metabolized, contrary to the iodine analog. We have developed a number of both calculational and experimental tools to understand the basic chemistry of astatine.

We studied the states of astatine in aqueous solution as a function of pH and Eh. While the expected existence of At- was confirmed with ion-exchange chromatography and electromobility measurements, we also observed higher oxidation states +I (At+) and +III (AtO+). In fact astatine is the only halogen capable of forming cations-- a further indication of the limitation of the iodine analog model. This is important because astatine cations can form complexes with organic ligands.

We believe that the in vivo instability of astatobenzoate-labeleled compounds is likely due to oxidative de-halogenation in biological components, lysomes in particular. 

Our calculations indicate that it may be possible to detect the heaviest possible tri-halogen species, IAtBr- .

Presented By: Gilles Montavon from SUBATECH, UMR CNRS, Nantes, France

Written By: William Carithers, Lawrence Berkeley National Laboratory

at the 10th International Symposium on Targeted Alpha Therapy (TAT-10)  May 31 - June 1, 2017 - Kanazawa, Japan.