Polymeric adsorbent for removing toxic proteins from blood of patients with kidney failure

A hypercrosslinked styrenic polymer with an enhanced proportion of mesopore s in the range 2-20 nm has been developed. The principle of the synthesis c onsists of the suspension polymerization of divinylbenzene (or copolymeriza tion of styrene with divinylbenzene) in the presence of a porogen that is a Theta-solvent for polystyrene. On the scale of thermodynamic affinity, The ta-solvents occupy a border position between good solvents and precipitatin g media for the growing polymer chains. In this case, microphase separation takes place during the final stages of the polymerization process. The pol ymer was shown to adsorb 93-98% of beta(2)-microglobulin from the blood or plasma of patients with chronic kidney failure. At the same time, large ess ential proteins, like albumin, are not removed to a significant extent, obv iously, due to the size-exclusion effect and the difference in the hydropho bicity of the proteins. By replacing surface exposed pendant vinyl groups o f the polymer with hydrophilic functional groups, the material was made hem ocompatible, according to the standard battery of biocompatibility tests re quired by ISO 10993 guidelines. No adverse effects such as fever or hypoten sion were noted in dogs in direct hemoperfusion experiments with the polyme r. (C) 2000 Elsevier Science B.V. All rights reserved.