Abstract
The effect of water vapor on physicochemical stabilities of ground mixtures of crystalline medicinals with microcrystalline cellulose (M.C.C.) was examined under various conditions of relative humidity (R.H.). Physicochemical stabilities of ground mixtures were measured by X-ray diffraction method and thermal analysis. In the case of the 10% diazepam and 90% M.C.C. ground mixture, the presence of diazepam crystal was observed at 30°C and 84% R.H., while nicotinamide crystals were not observed for the 10% nicotinamide and 90% M.C.C. ground mixture at 30°C and 100% R.H. It was estimated that hydrogen bonds in the cellulose were broken on moisture adsorption and that medicinal molecules or microassemblies of the molecules dispersed within the cellulose obtained the ability to move. And then diazepan molecules or microassemblies of the molecules were crystallized because of its poor solubility and nicotinamide, very soluble medicinal, was hydrated with adsorbed water or adsorbed water and the cellulose.
