Inclusion Compoundの医薬への応用 (第5報)

非イオン性界面活性剤の尿素付加物について

抄録

When nonionic surface-active agents of polyoxyethylene series are mixed with urea, the mixture solidified and the solid can be used as a powder or tablet. There is no evidence as to whether this solid is an inclusion compound or not. Mixtures of urea with various surfactants were prepared by the method of Barker and others and examination was made to see if hexagonal urea adduct has been formed through X-ray diffraction pattern. It was thereby found that the straight-chain alkyl ethers and esters of polyoxyethylene formed inclusion compound, like fatty acids and polyoxyethylene, while sorbitan alkylate and alkyl aryl ethers of polyoxyethylene did not form the inclusion compound. The latter is due to the fact that the size of sorbitan and benzene ring is larger than the channel of 5Å in diameter for formation of urea adduct. This nature can be utilized for the separation or fractionation of surfactants. For the preparation of urea adduct, it is more convenient to dissolve the two components in a solvent and to evaporate the solution to dryness. When a solvent is not used, formation of an adduct is facile with liquid surfactant but the adduct will not be formed easily without warming when the surfactant is a solid.