Radioiodination and biological evaluation of rabeprazole as a peptic ulcer localization radiotracer

Rabeprazole, a proton pump inhibitor, was labeled withI to giveI-rabeprazole in 98% yield. The optimum conditions were as follows: pH 8, 100 μg of chloramine-T, 30 min, and 0.2 mg of rabeprazole. The labeled compound was stable for 24 h. Biodistribution ofI-rabeprazole in mice after intravenous injection was studied, and its high uptake in stomach ulcer, reaching approximately 38% ID/g at 1 h post injection, was demonstrated. This concentration of the labeled compound in stomach ulcer is sufficient for ulcer imaging. The advantages of the method are simple labeling procedure, high labeling yield, and high sensitivity of ulcer imaging.