Radioiodination and biological evaluation of valsartan as a tracer for cardiovascular disorder detection

Abstract

A procedure for radioiodination of valsartan with iodine-125 is carried out via an electrophilic substitution of hydrogen atom with the iodonium cation I+. All reaction parameters were studied to optimize the labeling conditions of valsartan and to obtain a maximum radiochemical yield (RCY) of the 125I-Valsartan [125I-Val]. By using 3.7 MBq of Na125I, 50 μg of valsartan (0.2 mM) as substrate, 25 μg of Iodogen (0.15 mM) as oxidizing agent in ethanol at room temperature for 30 min, the radiochemical yield of 125I-Val was 98.6% The radiochemical yield was determined by electrophoresis using cellulose acetate moistened with 0.02 M phosphate buffer pH 7. The labeled compound was separated and purified by means of high-pressure liquid chromatography (HPLC). The biological distribution in normal mice indicates the suitability of radioiodinated valsartan to image any cardiovascular disorders.