T. C. Corby, P. Elworthy
Dec 1, 1971
Citations
0
Influential Citations
24
Citations
Journal
Journal of Pharmacy and Pharmacology
Abstract
Solubilization of some of the esters of p‐hydroxybenzoic acid by cetomacrogol 1000 solutions has been investigated by ultraviolet spectrophotometry, nuclear magnetic resonance spectrometry and viscometry to provide evidence on the environment of each part of the solubilizate molecule as well as the detergent molecule. Hydration of the micelles calculated from the viscometry results, gave further evidence on the site of solubilization of the compounds. On the basis of these results and solubility results published previously it is suggested that the compounds are solubilized as follows: p‐Hydroxybenzoic acid is wholly solubilized deep in the oxyethylene layer of the micelle. Ethyl p‐hydroxybenzoate is solubilized mostly in the oxyethylene layer and is situated adjacent to the core: some solubilization occurs within the core. Butyl p‐hydroxybenzoate is solubilized mainly at the oxyethylene‐hydrocarbon junction, the phenyl ring in the oxyethylene layer and the butyl chain in the core: some solubilizate is wholly present in the core. Methyl p‐methoxybenzoate: most of the compound is dissolved in the micellar core, but some is also present in the oxyethylene layer. Benzene is solubilized in a similar manner to methyl p‐methoxybenzoate.