The ability of antacids and cholestyramine to bind bile acids: effect of pH

Reflux of bile into the stomach may be injurious to the gastric mucosa. The ability of antacids and cholestyramine to bind bile acids is therefore potentially valuable in the treatment of reflux gastritis. The ability of antacids and cholestyramine to remove bile acids from gastric juice, hepatic bile, and solutions of commercially available bile acids was investigated in vitro over a pH range likely to occur in the stomach. The percentage of bile acids removed by antacids decreased with decreasing initial bile acid concentration and usually decreased as the incubation pH was increased from 3.6 to 7.0. Glycine-conjugated bile acids were bound to a greater extent than taurine-conjugated bile acids and dihydroxy to a greater extent than trihydroxy bile acids. Cholestyramine bound 97-100% of all bile acids in solution at pH 3.6 and pH 7.0. The effect of pH on adsorption should therefore be considered when antacids are used to treat gastritis.