Properties of agarose-encapsulated adsorbents. II. Elimination of endogenous and exogenous phenolic compounds from human serum.

Phenolic compounds derived from the amino acid tyrosine are endogenous toxins, which are believed to be involved in the pathogenesis of hepatic coma. There are also xenobiotic phenolic substances, such as p-hydroxy-acetanilide (paracetamol or acetaminophen), which can lead to serious complications if taken in an overdose. In both cases, a drastic therapeutic measure such as haemoperfusion may be indicated to eliminate the toxin from the blood. In the present work, human serum has been dosed with the phenolic compounds of immediate relevance in exogenous and endogenous intoxication, and the effectiveness of various adsorbent materials for the elimination of the toxins from the serum has been investigated. Resins and charcoal in the native state have been compared with those encapsulated into large agarose beads, a process which improves the haemocompatibility and thus the practicability of the adsorbents. A certain degree of specificity has been observed. Whereas phenolic acids are adsorbed quite effectively onto the strongly basic ion exchange resins of the Dowex 1X type, particularly 1X8 or 2X8, phenol or paracetamol are less effectively eliminated. In contrast to many other classes of toxin, the Amberlite XAD-type resins are ineffective for all the phenolic substances investigated. Charcoal is the most effective adsorber in most cases, particularly when encapsulated in powder form into agarose beads.