[125I]iodobenzoyl derivatives of acebutolol as potential myocardial imaging agents.

Three new iodobenzoyl derivatives of acebutolol, a cardioselective beta antagonist, were synthesized and labeled with iodine-125. The biodistributions of these labeled compounds were determined in normal rats and compared with that of thallium-201. Fifteen minutes following i.v. administration, the iodine-125-labeled meta- and para-iodobenzoyl acebutolols possessed the greatest ventricular uptake and the highest ventricle-to-blood and ventricle-to-lung ratios of the new agents. The corresonding values for thallium-201 were 2.5 to 3.0 times as high. The data in this study suggest that more lipophilic derivatives of the cardioselective beta antagonists will possess increased uptake and cardioselectivity, and thereby will compare more favorably with thallium-201 as myocardial imaging agents.