Properties of agarose-encapsulated adsorbents. I. Adsorption of digoxin from human serum.

The elimination of the cardioactive steroid, digoxin, from human serum by a range of adsorbent phases has been investigated. In the native state, the uncharged resins of the Amberlite XAD-type proved more effective than the ion-exchange resins, Dowex 1X, or active charcoal. Of the materials tested, Amberlite XAD-8 is by far the best suited resin for haemoperfusion in cases of digoxin overdose, whereby the less efficient XAD-4 is more commonly employed at present in clinics. In order to improve the haemocompatibility of the adsorbent materials, the technique of encapsulation into large agarose beads has been employed. In contrast to the effects observed with many other classes of xenobiotics, encapsulation into agarose beads results in a considerable loss of adsorptive capacity of digoxin by Amberlite XAD-8. The poor performance of active charcoal in form of granules can be improved by an order-of-magnitude using charcoal powder encapsulated in agarose. Thus, the latter material, or uncoated XAD-8 resin should be considered as a better alternative to materials in current use for extracorporeal detoxification in cases of digoxin overdose.