charcoal (3). A rather small amount of charcoal also would be less likely to come into rapid and complete contact with drug in the G I fluids than would a larger amount of the adsorbent and a larger dose of drug. In a sense, this represents a mass law effect under dynamic conditioiis where competitive processes (mainly absorption) are operative.
Andersen (13) showed that the iti uioo inhibitory effect of charcoal on drug absorption is quantitatively different in the rabbit and dog, possibly due to differences in rates of G I residence time. Similar quantitative differences are likely to exist between man and laboratory animals in general. It would seem, therefore, that [ti vitro adsorption studies, particularly when combined with desorption rate determinations using not only simple aqueous media but gastric and intestinal fluids, should be as useful in many instances as animal experiments for obtaining an estimate of the likely relative antidotal eflicacy of activated charcoal for drugs and other potential poisons. Rigorously controlled studies Li muti, as described in the previous report in this series (3), are mandatory for a quantitative assessment of the antidotal efficacy of activated charcoal with respect to the many drugs for which it may be used.