Development of 3-iodophenylisothiocyanate for radioiodination of monoclonal antibodies.

S Ram, D J Buchsbaum

Index: Int. J. Rad. Appl. Instrum. A. 43(11) , 1387-91, (1992)

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Abstract

A new radioiodination reagent, 3-iodophenylisothiocyanate (3-IPI) has been developed for coupling to monoclonal antibodies. The starting material, 3-tri-n-butylstannylphenylisothiocyanate was prepared via a reaction of hexabutylditin with 3-bromoaniline, followed by treatment with thiophosgene with an overall yield of 72%. The radioiodination of this tin precursor with Na[125I]I/iodogen in chloroform gave 3-[125I]IPI in 23-55% radiochemical yield and 81-99.6% radiochemical purity. Purification of the impure product by high pressure liquid chromatography increased the radiochemical purity of the product up to 99%. These results suggest that 3-IPI may be a useful ligand for radioiodination and coupling to a variety of monoclonal antibodies.