Synthesis of astatine-tagged methylene blue, a compound for fighting micrometastases and individual cells of melanoma

Investigation on electrophilic attaching of astatine-211 to methylene blue is carried out. Conditions for transferring astatine to a chemically active electrophilic form were found. A method for the production of astatine-211 -tagged methylene blue has been developed. The resulting radiopharmaceutica l preparation is free of the nonisotopic iodine carrier. The chromatographi c method of purifying simultaneously the product by anion-exchange resin QA E-Sephades A-25 allows it to pass into a 0.9% solution of sodium chloride ( physiological salt solution). The method provides the radiochemical yield o f astatine-211-tagged methylene blue as large as 68+/-6%.