Abstract
We determined fundamental properties and efficacy for a cosmetic ingredient of 2-(dimethyldocosylammonio) ethyl octadecyl ethyl phosphate (DOEP). It is a gemini compound that has a phosphorylcholine-like moiety. A gemini compound is known to exert unique properties such as high self-assembly and surface activity. The phosphorylcholine moiety is widely used in the life science field due to its high biocompatibility and safety. With these facts, DOEP was expected to have the doubled benefit of a gemini compound and a phosphorylcholine moiety. As an evaluation of fundamental properties, we observed the same assembly of DOEP in water that other gemini compounds tend to exert. We understood that DOEP has high self-assembly in the water phase, because it could form nano-size multi lamellar vesicles easily just by being stirred with a homogenizer. In this study, we evaluated both skin and hair for efficacies of DOEP as a cosmetic ingredient. About effects for the skin, DOEP had remarkable functions to cure the stratum corneum with improved transepidermal water loss and rising water content level. Observation of the hair surface with SEM showed DOEP also effected recovery of damaged hair cuticle. We considered these functions to have been brought about by the high self-assembly of DOEP. It formed multi lamellar-like hydrophobic layers on the surface of the skin and hair.
