Synthesis and preliminary evaluation of L‐6‐[ 123 I]Iododopa as a potential spect brain imaging agent

L‐6‐[ 123 I]Iododopa was synthesized by the exchange of 123 I for bromine on L‐6‐bromodopa in buffer(pH 4) for 35 minutes at 97°C. The synthesis was complete in approximately 1 hour with a radiochemical yield of 50%, a specific activity of 65 Ci/mmol and a radiochemical purity of ≥95%. A non radioactive standard of L‐6‐iododopa was synthesized by the iododemercuration of a mercury‐dopa derivative using I 2 in chloroform. It was shown that L‐6‐[ 123 I]iododopa accumulated in the rat striatum with striatum:whole brain ratio of 1.36 at 1 hour and 1.11 at 2 hours.