Physico-chemical aspects of the removal of protein-bound substances by charcoal and other adsorbents of potential value in systems of artificial liver support: Part 2—Kinetics of removal

The kinetics of removal of protein-bound substances implicated in liver failure are measured. The overall Sherwood number for their adsorption is shown in some cases to be equal to the film Sherwood number, implying film diffusion control. In other cases, significant nondiffusional resistances were found. For a homologous series of bile salts the Sherwood number was found to increase as the degree of protein-binding decreased. For bilirubin the mean free kinetic lifetime of the unbound species was shown to be an important factor in determining the maximum possible rate of removal. A mathematical model was proposed to represent the binding of substrate to peripheral tissue and the blood-tissue interchange rate evaluated by reference to clinical data. The model shows that perfusion times considerably longer than currently envisaged are required before significant quantities of bound materials can be removed from the tissue.