Biliary Excretion of Contrast Media

Abstract

Experimental data are reported concerning the biliary excretion, urinary excretion and plasma protein-binding of a new organic iodine compound, coded B 9720, versus the corresponding values of two known contrast media for cholangiography—ioglycamic acid and iodipamide. In dogs, the biliary excretion of all three products is determined exclusively by active transport processes; the maximum transport value for ioglycamic acid proved greater than the corresponding values for iodipamide and B 9720. In rats, instead, the excretion of these products into the bile is a nonsaturable process. From these experimental data it appears that there is no direct relationship between the maximum biliary excretion velocity (Tm) and the degree of affinity for plasma proteins of these compounds. A strong protein-binding, nevertheless, precludes not only the urinary but also the biliary excretion at low plasma levels, when all molecules of the contrast medium are bound to plasma proteins.