[Influence of pH in the adsorption capacity of bile salts and lysolecithins in vitro by antacids containing clay and/or aluminum].

In vitro binding properties of eight clay and/or aluminium-containing antacids for bile salts and lysolecithin were measured in comparison with cholestyramine binding capacity, taking into account the final medium pH. Dihydroxy-bile salt adsorption was greater when the initial pH was 1.8 and the intensity varied according to the drugs. Trihydroxybile salts were less bound and the binding was less related to the medium pH. Lysolecithins were bound by clay-containing antacids with the same intensity as cholestyramine, while the binding capacity of aluminium-containing antacids was weaker and related to the final pH. There were close relationships between binding capacities and the final pH so that bile salts are bound by antacids with a great intensity in acid medium and released by alkalinisation in contrary to the binding capacity of cholestyramine. Lysolecithins should be also bound more intensively in acid medium by aluminium-containing antacids. Binding capacities of the antacids were related to their composition, their antacid effect and to the final pH.