title: Synthesis and biodistribution of 125I labeled bivalent analogs of practolol as potential myocardial imaging agents.
abstract: Iodinated bivalent ligands 3 and 4 and a monovalent ligand 5 were prepared from the cardioselective beta-antagonist, practolol. 125I-labeled 3, 4 and 5 were prepared by solid phase isotopic exchange reaction with carrier-free Na125I and examined in rats as potential receptor-site-directed myocardial imaging agents. Biodistribution of these agents in rats indicated that 125I-3 and 125I-4 were localized in the heart similarly to 125I-5 and the [125I]iodobenzoyl (6) that was previously reported. Localization of 125I-3 and 125I-4, was more persistent in the heart than that of 125I-monovalent ligands 5 and 6. Heart-to-blood ratios of 125I-3 and 125I-4 were significantly lower than those of 125I-5 and 125I-6, due mainly to slow blood clearance rates of 125I-3 and 125I-4.
mesh_terms: D000818:Animals; D006321:Heart / Q000000981:diagnostic imaging*; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D007700:Kinetics; D011217:Practolol / Q000031:analogs & derivatives* / Q000378:metabolism; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
chemical_list: D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D011217:Practolol