Synthesis and ~(131)I Labeling of Epidepride as a Dopamine D_2 Receptor Imaging Agent

S (-) N (1 ethyl 2 pyrrolidinyl)methyl 5 iodo 2,3 dimethoxybenzamide (Epidepride) and its iodine labeling precursor S (-) N (1 Ethyl 2 pyrrolidinyl)methyl 5 tributyltin 2,3 dimethoxybenzamide are synthesized from 3 methoxy salicylic acid. The labeling precursor is labeled with 131 I by hydrogen peroxide method, and 131 I epidepride is gained, its radiolabelling yield(RLY) and the radiochemical purity(RCP)are all over 95%. The RCP of 131 I epidepride is over 90% under 4 ℃ after 15 days. 131 I epidepride has high affinity to dopamine D 2 receptor The striatal uptake can be blocked completely by spiperone. The striatum and cerebellum uptake ratio can reach 237 at 320 min in rats.The results show that 131 I epidepride may be used as a dopamine D 2 receptor imaging agent for SPECT.