抄録
In order to establish the therapeutical significance of the molecular compound composed of organic medicinals, dissolution behaviors of both the one-to-one molecular compound of sulfanilamide and sulfathiazole and the corresponding mechanical mixture were investigated at 15, 25, and 35°. Soon after the dissolution of the molecular compound, both components showed a fixed and the same concentrations for several time which is attributable to the metastable solubility of the molecular compound itself. By further stirring of the solution and the solid residue, the compound was gradually decomposed by water, and the stable equilibrium of the system was finally attained, at which the total concentration of sulfanilamide was larger than that of sulfathiazole. Stability constants of the compound at these temperatures were determined. As was expected, the constants at the stable equilibria agreed well with the ones at the metastable equilibra. In the case of the mechanical mixture, the dissolution curves were completely different from those of the former, and neither of the components showed a constant concentration during the course of experiment. The difficulty of attainment to the solution equilibrium would be mainly attributed to the fact that sulfathiazole particles in the residue were coated with the molecular compound deposited from the solution. Thus, it may be concluded that the absorption pattern of the molecular compound will be different from that of the mechanical mixture, since dissolution into the intestinal fluid prior to absorption will take place in an analogous manner to that observed in the above.
