Effect of various alcohols on intestinal net water flux and theophylline absorption in rats

Previous studies in this laboratory demonstrated that the rate of intestinal absorption of theophylline in rats is increased significantly by ethanol in low concentrations and that this absorption enhancing effect is associated with an increased net water flux from the intestine. It is now shown that other alcohols, namely methanol, n-propanol, n-butanol, glycerin, propylene glycol, and, to a lesser extent, mannitol and sorbitol, can also increase net water flux from the small intestine of anesthetized rats. Polyethylene glycol 200 and 400 had no such effect, suggesting that these compounds do not penetrate to a site of action that elicits the increased net water flux. At initial concentrations of 0.1 and 1.0 M, glycerin and propylene glycol increase significantly the intestinal absorption rate of theophylline from the small intestine of anesthetized rats. The results show that the theophylline absorption enhancing effect of ethanol is not limited to that particular alcohol.