ABSORPTION OF PHENOL RED AND BROMPHENOL BLUE AS MODEL-DRUGS FROM THE PERITONEAL-CAVITY AROUND THE LIVER SURFACE IN RATS

The importance of the injection site on the pharmacokinetics of phenol red and bromphenol blue as model drugs after intraperitoneal administ ration into rat was examined. Their absorption rate from the peritonea l cavity was faster after intraperitoneal administration to the liver surface than that after intraperitoneal administration to the distal s mall intestine, as shown by the increase in maximum concentration and decrease in mean residence time in plasma. A similar tendency was obse rved in the biliary excretion pattern. The enhanced absorption rate wa s supported by the significantly smaller amount of both drugs remainin g in the peritoneal cavity at 15 min after liver surface administratio n than that after small intestine administration. The liver concentrat ion of the model drugs at 15 min after liver surface administration wa s 1.5-2.0 times that after small intestine administration. Accordingly , liver surface administration was shown to be effective with good abs orption and efficient drug delivery to the liver.