Evaluation of Five Activated Charcoal Formulations for Inhibition of Aspirin Absorption and Palatability in Man

Abstract

The relative effects of five activated charcoal formulations on the absorption of orally administered aspirin and the relative palatability of these formulations were studied. The excipients sorbitol, carboxymethylcellulose sodium, starch, chocolate syrup and mineral oii emulsion were used to prepare five activated charcoal formulations. In a randomized, complete crossover aspirin adsorption study, eight adults ingested, following administration of an oral aspirin dose of 972 mg, formulations containing 20 g of activated charcoal alone or with one of the five excipients. As a control, the subjects also ingested 972 mg aspirin but activated charcoal was not administered afterward. Urinary excretion of total salicylate was measured by spectrophotometry over the 72-hour period after aspirin administration. For the palatability study, the five excipient formulations, each containing 10 g of activated charcoal, were administered to 22 adults using a randomized, complete crossover, single-blind, pair comparison design. The formulations were evaluated on overall preference, grittiness, ability to be swallowed, and taste. The in vitro aspirin adsorption of the mineral oil formulation, with and without surfactants, also was measured. Four formulations were statistically equivalent (p > 0.05) to the plain activated charcoal slurry in reducing aspirin absorption. The same four formulations were far more palatable than . the slurry. The formulation employing mineral oil emulsion did not effectively inhibit aspirin absorption. The in vitro study showed mineral oil was responsible for the reduced adsorption of the mineral oil formulation. Further studies are needed to evaluate the effects of these formulations on absorption of other drugs.