Radioiodination and Biological Evaluation of Epinephrine as a Possible Adrenergic Receptors Imaging Agent

An adopted method for the preparation of high radiochemical purity [125I] iodoepinephrine was developed in order to characterize the binding properties of adrenergic receptors. Direct radioiodination of epinephrine was carried out using chloramine-T as oxidizing agent. The reaction proceeds well within 15 min at ambient room temperature up to 25+1ºC and afforded a radiochemical yield up to 94%. Different chromatographic techniques (electrophoresis and paper chromatography) were used to evaluate the radiochemical yield and purity of the labeled product. Biodistribution studies were carried out in normal Albino Swiss mice and the results showed rapid and high cardiac uptake of 125I-epinephrine. The result indicates the possibility of using radioiodinated epinephrine as myocardial imaging agent.