The purpose of this article is to study the preparation and biodistribution in animals of dopamine D2 receptor ligand 131 I-epidepride. Epidepride was 131 I radioiodinated with hydroperoxide or chloramine-T method. The purity and stability of 131 I-epidepride were studied by HPLC and TLC

the dynamic distribution in brain and critical organs of SD rats were studied. The radiolabelling yields of 131 I-epidepride were 97.4% and 52.9% respectively. With no more purification

the hydroperoxide method is better than the chloramine-T method. After 4 hours in room temperature

the radiochemical purity of 131 I-epidepride was still over 90%. The striatum uptake was good

the striatum/cerebellum ratio reached 237:1 at 320min. Among the critical organs

lung had the first and the highest uptake. All organs had quick clearance ( T 1/2 <4h). The radioactivity in thyroid increased with time. The results show that 131 I-epidepride has a high striatum uptake and a high striatum/cerebellum ratio. 131 I-epidepride is a good dopamine D2 receptor agent