Binding properties in vitro of antacids for conjugated bile acids.

The binding properties of various commercial antacids for pure conjugated bile acids in an aqueous solution or the bile acids present in human gallbladder bile were characterized. Aluminum hydroxide was a potent binding agent, similar in affinity and capacity to cholestyramine. With aluminum hydroxide, dihydroxy bile acid conjugates were bound more strongly than trihydroxy bile acid conjugates, and glycine conjugates were bound more strongly than taurine conjugates; pH had no effect per se on binding. Magnesium hydroxide and aluminum phosphate bound bile acids much more weakly. Aluminum hydroxide warrants exploration in therapeutic situations in which bile acid binding is sought.