Evaluation of the toxin-to-protein binding rates during hemodialysis using sorbent-loaded mixed-matrix membranes

The transport and reaction phenomena that take place in multi-layered mixed-matrix membranes with activated carbon (AC) sorbents that are expected to improve extra-corporeal blood purification, are studied at the macroscopic scale. A model was developed that aims at the description of the removal efficiency of harmful uremic toxins from the blood in the presence of carbon-adsorptive particles and produces results that are aligned with the experimental data. The importance of the generally unknown kinetic rate constants of the association of toxins to albumin is investigated through sensitivity analysis. Matching with further experimental data allowed the extraction of vital kinetic rate constants for key uremic toxins such as indoxyl sulfate (IS) and p-cresyl sulfate (PCS). Moreover, the effects of the plasma composition, as well as of the membrane loading with activated carbon, on the total removal of the protein-bound toxins are quantified and discussed.