80945-46-6Relevant articles and documents
The production and characterization of medium and high specific activity 125I-T3 and 125I-T4 utilizing substitution and exchange mechanisms
Reese,Hales
, p. 555 - 568 (2007/10/17)
The reactions of 125I with 3,5-diiodo-L-thyronine (T2), 3,3',5-triiodo-L-thyronine (T3), and L-thyroxine (T4) have been studied under various pH and concentration conditions. It was found that when the pH is 7.5 and approximately equimolar amounts of thyronine substrate and 125I are reacted, T2 produces as the major product monolabeled T3 of high specific activity (~3300 mCi/mg) and long term stability while T3 produces as the major product approximately 30% dilabeled 125I-T4 with short term stability and a specific activity of ~3000 mCi/mg. Simple methods for purification of this product to make it useful are discussed. When the pH is raised to 8.7 and the molar ratio of 125I to thyronine substrate is increased to 1:6 then T3 produces as the major product T3 of medium specific activity (~500 mCi/mg) and long term stability while T4 produces very stable monolabeled T4 of medium specific activity (~250 mCi/mg). The mechanisms of substitution and exchange, as they relate to the formation of these and other side products in these reactions, are discussed.
