Phase inversion of W/O emulsions by adding hydrophilic surfactant — a technique for making cosmetics products

W/O emulsions can be inverted to O/W systems by adding hydrophilic emulsifier. This has been studied with the emulsifier combination rapeseed sorbitol ester (hydrophobic) and lauroyl glutamate (hydrophilic). Phase inversion occurs at a well defined amount of hydrophilic emulsifier. This critical quantity of hydrophilic emulsifier depends on the emulsion recipe, in particular the water/oil ratio. Stable O/W model cosmetics emulsions can be made by this method. Unlike the PIT emulsification technique, temperature dependent surfactant properties are not required, so this method can also be used with non-ethoxylated emulsifiers.