Studies on microemulsions using Brij 96 as surfactant and glycerin, ethylene glycol and propylene glycol as cosurfactants

The existence of microemulsion regions was investigated in quaternary systems composed of Brij 96.cosurfactant/mineral oil/water by constructing phase diagrams. The cosurfactants used were glycerin, ethylene glycol and propylene glycol, all of which are polyhydroxy compounds used widely in the pharmaceutical industry. Light scattering data was used to determine the diameter of the internal phase as a function of the surfactant:cosurfactant ratio at a constant internal phase/oil ratio. Results suggest that the surfactant:cosurfactant ratio is an important parameter in determining the size of the internal phase of these microemulsion systems.