99mTc-labelling of mercaptoacetyltriglycine and its related compounds

Mercaptoacetyltriglycine and its related compounds were synthesized and labeled with 99mTc-radionuclide in order to study the effect of substituents and labeling conditions upon the formation of radioactive byproducts. Direct labeling and ligand exchange reactions were followed by radio-TLC separation. The direct labeling in alkaline media at elevated temperature provides high radiochemical yields and gives opportunity for a new kit formulation because the neutralization to physiological pH does not cause any change in the chemical identity of the complexes. Compounds with the strongly polar sulfonyl groups show significantly lower protein binding compared with mercaptoacetyltriglycine and may be considered as potential renal agents. (author) 8 refs.; 5 tabs