Synthesis and biologic distribution of radioiodinated beta-adrenergic antagonists.
Iodinated analogues 2, 7, and 8 were prepared from propranolol, practolol, and acebutolol in 30--50% yields. Radioisotopic exchange between carrier-free Na125I and the molten iodinated beta-adrenergic antagonist yielded the corresponding 125I-labeled product. The biodistribution in rats, determined at 15 and 60 min postinjection, indicated that the radioiodinated analogues of the cardioselective drugs practolol and acebutolol localized to a greater degree in the liver and heart than the analogue of propranolol. Conversely, [125I]iodopropranolol (2) was concentrated to a greater extent in the lungs than [125I]iodopractolol (7) or [125I]iodoacebutolol (8). Therefore, 123I- or 131I-labeled cardioselective beta-adrenergic antagonists, such as 7 or 8, may prove useful as radiodiagnostic agents for the external imaging of the myocardium.
D000070:Acebutolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D000319:Adrenergic beta-Antagonists / Q000138:chemical synthesis* / Q000378:metabolism; D000818:Animals; D006321:Heart / Q000000981:diagnostic imaging; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D011217:Practolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D011433:Propranolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D011877:Radionuclide Imaging; D051381:Rats; D014018:Tissue Distribution
D000319:Adrenergic beta-Antagonists; D007457:Iodine Radioisotopes; D000070:Acebutolol; D011433:Propranolol; D011217:Practolol