Coated charcoal haemoperfusion

Abstract

We have made use of the principle of artificial cells to microencapsulate charcoal by coating an ultrathin membrane directly on to the surface of individual activated charcoal granules. This way the enclosing membrane prevents any free powder from going into the circulation. At the same time, blood platelets are prevented from being removed by the activated charcoal. Since 1970, we have been carrying out clinical trials in patients for acute drug poisoning, chronic renal failure, liver failure and other conditions. Our earlier results have stimulated a number of other polymer coated charcoal systems to be studied and produced in a number of other centres. At present there are at least ten coated charcoal haemoperfusion devices being used. They vary somewhat in membrane thickness, membrane permeability, blood compatibility and efficiency. It is therefore important not to make generalizations based on the results obtained for the less effective and less blood compatible systems. Collodion (cellulose nitrate) membrane coated charcoal is sufficiently blood compatible for use in uraemia and acute intoxication. In conditions with very sensitive platelets (e.g., hepatic failure) we showed earlier that by adsorbing albumin on to collodion, a highly blood compatible system can be obtained. This approach has been extended in three ways: instead of albumin, protein A can be incorporated into the collodion coating, resulting in an immunosorbent system for clinical trial in cancer therapy; albumin can be used to coat synthetic immunoadsorbent for blood group antibody to allow clinical application; albumin can also be used to coat resins to make them blood compatible.(ABSTRACT TRUNCATED AT 250 WORDS)