Influence of lamellar liquid crystal structure on percutaneous diffusion of a hydrophilic tracer from emulsions

The purpose of this study was ro investigate the effect of a lamellar liquid crystalline phase in emulsions on percutaneous diffusion of a hydrophilic sunscreen (benzophenone-4). Six emulsions were formulated, using all the same components except the surfactants. The emulsion structures were visualized by freeze-fracture electron microscopy. In vitro penetration measurements were performed with static diffusion cells. Benzophenone-4 fluxes were smallest for emulsions without liquid crystals and highest for those with liquid crystals. The permeant fluxes seemed to be modified by the surfactant organization within the emulsions.