Disposition of intravenous 123iodopentamidine in man.

This study compared the disposition of the radiopharmaceutical [123I]iodopentamidine with that of pentamidine after intravenous infusion by measuring plasma concentrations of each using scintilation counting and high-performance liquid chromatography (HPLC), respectively. There was rapid hepatic uptake and biliary excretion of the 123I label. Distribution kinetics of the 123I label were similar to those of pentamidine, but its elimination half-life (41 +/- 27 h) was longer than that of pentamidine measured by HPLC (11 +/- 8 h). [123I]iodopentamidine distribution reflects that of pentamidine, but elimination of the radiopharmaceutical appears slower.