1961 年 81 巻 12 号 p. 1684-1688
Effect of chemical structure of surface active agents on the stabilization of acetylsalicylic acid was examined by the use of nonionic surfactants, such as higher alcohol ethers of polyoxyethylene and fatty acid esters of polyoxyethylene sorbitan, in aqueous solution of pH 1 in which acetylsalicylic acid would be present as a nondissociating type. With the series of nonionic surfactants tested, those with stronger degree of lipophilic character seemed to be more effective for stabilization.
Examination of activation energy at the time of addition of various surfactants revealed that activation clearly increased in the systems added with surfactant. The quantity of acetylsalicylic acid dissolved by addition of a surfactant was measured and the greater the quantity, the greater was the stabilization.
These experiments indicated that stabilization of the non-dissociating form of acetylsalicylic acid by nonionic surface active agents was due to solubilization of this acid into the micelle.