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Preparation of [ 123 I]‐ and [ 125 I]epidepride: A dopamine D‐2 receptor antagonist radioligand
Author(s) -
Clanton J. A.,
de Paulis T.,
Schmidt D. E.,
Ansari M. S.,
Manning R. G.,
Baldwin R. M.,
Kessler R. M.
Publication year - 1991
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580290703
Subject(s) - chemistry , radioligand , radiochemistry , biodistribution , nuclear chemistry , iodine 123 , nuclear medicine , receptor , biochemistry , in vitro , medicine
( 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.