In vitro bile acid adsorption by bismuth subsalicylate and montmorillonite

We investigated the capability of Pepto-Bismol and its components (Veegum and bismuth subsalicylate) to sequester bile acids from aqueous solution in vitro and compared it to that of cholestyramine. Through a pH range of 3-9, all substances tested sequestered free and conjugated bile acids in quantities directly related to the concentration of the sequestering agent within the incubation mixture. Veegum was more effective gram for gram than bismuth subsalicylate. Pepto-Bismol, whose sequestering capacity approximated cholestyramine's, absorbed more than either of its components alone. The relationship between Pepto-Bismol's in vitro bile acid binding and its in vivo antidiarrheal properties is unknown.