Preparation and performance of cross-linked agar encapsulated activated charcoal (CAAC-III).

A technique is described to encapsulate activated charcoal for hemoperfusion to be used in an artificial liver support. Spherical activated charcoal was coated with agar and shaped in organic solvent, as well as cross-linked by epichlorohydrin (40-50 degrees C). The product withstood autoclaving at 121 degrees C for 0.5 hours, and had a good adsorption ability for compounds with molecular weight ranging from 113-5200. The adsorption kinetic showed pore diffusion limitation to compounds of small molecular weight, and film diffusion limitation to compounds of large molecular weight. Microparticles of charcoal release were greatly reduced, and within the permissible range according to the requirements in the U.S. Pharmacopeia (1985).