In vitro binding and metabolism of iopronic acid by rat liver microsomes.

Summary Iopronic acid (2-{2-[(3-acetamido-2,4,6-triiodophenoxy)-ethoxy]- methyl}- butyric acid), a cholecystographic agent, is metabolized by rat liver microsomes to hydroxyethyl-(3-acetamido-2,4,6-triiodophenyl)ether and to 3-acetamido-2,4,6-triiodophenoxy-acetic acid. This metabolism is oxygen- and NADPH-dependent, and it is inhibited by CO. The addition of iopronic acid to microsomes causes a type II spectral change. The in vitro results are in good agreement with the in vivo data already available showing that iopronic acid is metabolized to a limited extent and that the three iodine atoms present in the parent compound are also found in the metabolites.