In vitro study of boric acid and activated charcoal.
An in-vitro study utilizing a titration assay was performed to evaluate the degree of adsorption of one gram of boric acid by 7.5 g, 15.0 g and 30.0 g of activated charcoal. The mean percentage adsorbed was 5.7 +/- 1.6% for 7.5 g of activated charcoal, 17.6 +/- 3.5% for 15.0 g of activated charcoal and 38.6 +/- 6.3% for 30.0 g of activated charcoal. Analysis of variance showed a significant difference from the control (no activated charcoal) for the 15.0 and 30.0 g samples (p less than 0.05). Although binding of boric acid by activated charcoal increased as the proportion of activated charcoal to boric acid increased, this finding is not clinically significant since the amount of activated charcoal required for 38% adsorption is 30 times the amount of boric acid ingested. Considering the toxic and potentially fatal doses of boric acid in children (5 g) and adults (20 g), doses of activated charcoal of greater than 150 g in children or 600 g in adults would be impractical for the clinical situation.