Preparation, chromatographic evaluation and biodistribution of 99mTc-procainamide as a radiopharmaceutical for heart imaging

Abstract

Abstract Procainamide (4-amino-N-[2-(diethylamino) ethyl] benzamide) is a sodium channel blocker, which acts as an effective antiarrhythmic agent used in the treatment of a variety of atrial and ventricular arrhythmias. The aim of this study was to prepare 99mTc-procainamide complex, apply different chromatographic techniques for the assay of radiolabeling yield and study its biodistribution as a novel radiopharmaceutical for heart imaging. 99mTc-procainamide was obtained with a maximum labeling yield of 95.76±0.20% via direct labeling method under optimum conditions of 200 μg of procainamide, 300 μL of buffer (carbonate) at pH 11, 30 μg SnCl2·2H2O at room temperature (25°C) for 15 min. In terms of in vitro stability, the complex was stable for 3 h. Chromatographic evaluation using paper chromatography, thin layer chromatography, gel chromatography, and high performance liquid chromatography showed reliable results for measuring the radiochemical yield. Biodistribution study of 99mTc-procainamide showed ratios of heart/lung and heart/liver (6.38±1.50, 2.06±0.31, respectively at 30 min post injection) which was comparable to that of 99mTc-sestamibi (7.4±2.00, 0.97±0.10, respectively at 60 min, P<0.05).