Abstract
The detoxication of quinine sulfate as a model drug by a multiple (water-in-oil-in-water, w/o/w) emulsion was evaluated in vitro and in vivo. In vitro drug extraction into the emulsion was determined using a dialysis system. Drug extraction into the emulsion increased with increasing volume fraction of water-in-oil (w/o) emulsion in the w/o/w system (Fw/o/w). However, when 0.01 N HCl, which has the same pH as the stomach, was selected as a continuous aqueous solution of the emulsion, quinine was hardly extracted into the emulsion regardless of the Fw/o/w values. Thus, we attempted the simultaneous use of the emulsions and an antacid (NaHCO3) in order to increase the pH in the continuous phase of the emulsion, but combined use of the antacid increased the viscosity of the system. From the viscosity data of the emulsions and further in vitro extraction data, in vivo experiments were carried out with a suitable emulsion (Fw/o/w=0.2). The blood concentration of quinine co-administered with the multiple emulsion containing the antacid in rabbits was significantly lower than that in the control. These results indicate that the use of multiple emulsions may be a promising new approach to the emergency treatment of drug overdose.
