Abstract
The effects of bile salts, sodium taurocholate and sodium glycocholate, on drug absorption from the rat small intestine were investigated using the in situ perfusion technique. There are three likely mechanisms by which bile salts can effect drug absorption from the rat small intestine ; first, the loss of thermodynamic acitivity of a drug due to the formation of the micellar complex ; second, the local concentration build-up effect such as an accumulation on the absorptive surface ; third, the direct effect on the permeability characteristics of the intestinal mucosa. The absorption of sulfanilamide was not affected, but the absorption of sulfaguanidine and phenol red, poorly absorbable drugs, were enhanced by bile salts above their critical micellar concentration. On the other hand, the absorption of 2-allyloxy-4-chloro-N-(2-diethylaminoethyl) benzamide hydrochloride (A. C. D. B.) was inhibited by bile salts above the critical micellar concentration. Possible mechanisms of these effects are discussed.
