[Characteristics of barbiturate adsorption on activated charcoal]

Equilibration patterns of barbiturates adsorption on activated charcoals were studied using aqueous solutions of barbital and sodium barbital and commercially available charcoals BAU, AR-3, AR-B, AR-A, SKT-6A. The rate of barbiturates adsorption was described as an additive function of concentrations of amide, ionized and non-ionized imidol forms calculated considering the reactions of dissociation and hydrolysis. Relatively low equilibrium concentrations of barbiturates in the solid phase and simultaneous sorption of the barbital anion as well as of its non-ionized form were related to the considerable rate of the substance ionization due to both tautomeric transformation and dissociation of the acid formed. The procedure for calculation of equilibrium described assumes that the rate of barbital and sodium barbital adsorption on activated charcoals of various brands might be estimated at various pH values of a solution, based on dissociation and hydrolysis reactions, which is of importance under conditions of the barbiturates enterosorption.