Mechanism of intestinal absorption of drugs from oil in water emulsions. II. Absorption from oily solutions.

Abstract

Drug absorption from oily solutions was investigated by the rat large intestine using in situ re circulation technique. Three model drugs (acetanilide, sulfapyridine, and salicylamide) and three different kinds of oil (isopropyl palmitate, ethyl laurate, and diethyl phthalate) were chosen for absorption studies.It was found that in oily solution, drug absorption through the large intestinal membrane usually took place after being liberated from oil into the secreting fluid.In the absorption of a drug having oil/water partition coefficient of less than one, apparent enhancement in the absorption was observed. This was attributed to the small volume of secreting fluid (aqueous phase) and the local concentration build-up of a drug at the absorptive surface.Some comparisons have been made with the absorptive behavior of drugs from oil in water emulsions.