Development of Novel Cosmetic Base Using Sterol Surfactant. I. Preparation of Novel Emulsified Particles with Sterol Surtactant

We have developed various kinds of ultrafine emulsifying methods using random copolymer of polyoxyethylene (POE)/polyoxypropylene (POP) dimethyl ether [EPDME]. Among ultrafine emulsions made by these methods, it was revealed that an O/W type emulsion, which had prepared with EPDME, sterol surfactant, and polar oils, had a unique structure that had a lamellar structure on the surface of emulsified particles. To clarify the character of the particles and the mechanism of the emulsification, investigation using small angle X-ray scattering (SAXS) measurement and the phase diagram of the emulsion system was done. FF-TEM observation indicated that a few lamellar layers were deposited from the oily ingredients on the surface of the emulsified particle. It was also presumed that the lamellar structure was formed with sterol surfactant and polar oil. The phase diagram analysis suggested that EPDME could form emulsified particles having lamellar structure on the surface of the particle with hydrophilic sterol surfactant, in polar oils.