Closo-dodecaborate (2-) anion as a potential prosthetic group for attachment of astatine to proteins. Aspects of the labelling chemistry with chloramine-T

Closo-dodecarborate (2−) was proposed as a prosthetic group for direct labelling of proteins with 211At for radionuclide therapy. Astatination of closo-dodecarborate (2−) anion using Chloramine-T was studied, and the influence of pH, reaction time, amount of substrate and oxidant was determined. A maximum labelling yield of 55–75% was found in the pH range 7–8. A spontaneous astatination of closo-dodecarborate (2−) in the absence of Chloramine-T was also found, presumably due to generation of oxidising products from water radiolysis. Our results indicate that derivatives of closo-dodecarborate (2−) anion may be used as prosthetic groups for direct labelling of proteins. Copyright © 2000 John Wiley & Sons, Ltd.