Preparation of [123I]- and [125I]epidepride: A dopamine D-2 receptor antagonist radioligand

✍ Scribed by J. A. Clanton; T. de Paulis; D. E. Schmidt; M. S. Ansari; R. G. Manning; R. M. Baldwin; R. M. Kessler

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: French
• Weight: 412 KB
• Volume: 29
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2580290703

✦ Synopsis

Abstract

(S)‐(−)‐N‐[(1‐ethyl‐2‐pyrrolidinyl)methyl]‐5‐[^123^I]iodo‐2,3‐dimethoxybenzamide (TDP 517) (proposed generic name, [^123^I]epidepride) is the iodine‐123 substituted analogue of isoremoxipride (FLB 457), both of which are very potent dopamine D‐2 antagonists (epidepride K~D~ 0.024 nM). [^123^I]Epidepride was radioiodinated in 60–70% radiochemical yields in 35 min from the corresponding 5‐(tributyltin) derivative using Na^123^I with a specific radioactivity of 3000 Ci/mmol, and oxidized in situ with chloramine‐T. The aryltin precursor was prepared from non‐labelled epidepride by palladium‐catalyzed stannylation using bis(tri‐n‐butyltin) in triethylamine. Alternatively, using no carrier‐added Na^125^I as the radioisotope, [^125^I]epidepride at 2000 Ci/mmol specific radioactivity was prepared in 86% radiochemical yield and 99% radiochemical purity after purification by reverse phase HPLC in ethanolic phosphate buffer.