In Vitro Adsorption Characteristics of Bile Salt Anions by Activated Carbon Beads for Oral Administration

Abstract

Adsorption characteristics of bile salt anions by activated carbon beads consisting of about 67% activated carbon powder in agar were studies in vitro and compared with those of a cholestyramine preparation from the standpoint of usefulness for sequestering bile salts in the intestine. Although the rate of adsorption of bile salts by the activated carbon powder in the beads was somewhat reduced as compared with that of the naked powder, the adsorption capacity was essentially retained in the beads, and was enhanced by the presence of physiologic anions. The interfering effect of physiologic anions on the adsorption by cholestyramine resin preparation was greater for trihydroxy bile salts than for dihydroxy analogs. Thus, the beads showed a greater capacity for trihydroxy bile salts than the resin preparation. For dihydroxy analogs the opposite relationship was observed, i.e., the capacity of the resin preparation was greater than that of the beads. In the presence of triolein, the adsorption of bile salts by the powder was greatly impaired, whereas that by the beads was only slightly reduced. Encapsulation of the powder by agar apparently permitted selective adsorption of bile salts in the presence of the lipid.