Effect of type and amount of carboxymethylcellulose on in vitro salicylate adsorption by activated charcoal.

The effect of the type of carboxymethylcellulose (CMC) and amount of CMC used in preparing antidotal charcoal formulations on the in vitro kinetics of sodium salicylate adsorption from simulated gastric fluid was assessed in agitated vessels of two designs. Mixtures made with low, medium, and high viscosity CMC were tested. Additionally, the effects of the charcoal and water contents of these mixtures on adsorption kinetics were considered. The results suggest that charcoal mixtures which are fluid enough to be pourable (hence, drinkable) are strongly to be preferred from the standpoint of rate of adsorption. More particularly, gel-like formulations should be avoided because they disperse poorly and result in rather slow rates of drug uptake.