The biliary and urinary excretion of sodium tyropanoate and sodium ipodate in dogs: pharmacokinetics, influence of bile salts and choleretic effects with comparison to iopanoic acid.

The biliary and urinary excretion of sodium tyropanoate (Bilopaque) and sodium ipodate (Oragrafin) were studied in unanesthetized bile-fistula dogs using stepwise, increasing, intravenous infusions of the contrast materials. A constant intravenous infusion of sodium taurocholate was administered at the rate of either 0.5 or 2.0 mu moles per min per kg throughout each experiment. The biliary excretion of sodium tyropanoate or sodium ipodate was not effected by the rate of sodium taurocholate infusion. The maximum rate of biliary excretion of sodium ipodate was significantly greater than that of sodium tyropanoate with the low taurocholate infusion, but there was no significant difference between the two with the high taurocholate infusion. With the low taurocholate infusion the maximum biliary excretion rate of sodium tyropanoate (0.956 mu moles per min per kg) and sodium ipodate (1.472 mu moles per min per kg) were significantly greater than the maximum biliary excretion of iopanoic acid (Telepaque) (0.671 mu moles per min per kg). With the high taurocholate infusion the maximum biliary excretion rates of the three contrast agents were not statistically different. Both sodium tyropanoate and sodium ipodate produced an increase in canalicular bile flow (8-11 ml per millimole). These data suggest that in clinical cholecystography sodium tyropanoate and sodium ipodate are not excreted in bile more rapidly than iopanoic acid, except when the rate of biliary excretion of bile salts is low; that is, except in patients who are fasting or those who are on a fat-free diet.