Role of intestinal mucus in the absorption of quinine and water-soluble dyes from the rat small intestine.

Abstract

Role of intestinal mucus in the absorption of quinine and 4 water-soluble dyes, methylene blue, bromthymol blue, bromphenol blue and phenol red, from the rat small intestine was investigated. Immediately after pretreatment with pH 6.5 buffer solution for 10 min and a recovery period of 15 min after the pretreatment, absorption experiments were performed at pH 6.5 using the in situ perfusion technique and in vitro uptake method by the everted sacs. The results of determination of protein and neutral sugar suggested that mucus was secreted during the recovery period of 15 min after the pretreatment with pH 6.5 buffer solution. All drugs examined bound to mucus prepared from intestinal washings after the recovery period of 15 min. The mucosal surface of the small intestine, mucus layer, apparently has an important role in the absorptive process of quinine and 4 water-soluble dyes.