Monoalkyl phosphates (MAPs) and other various anionic surfactants were evaluated as skin cleansers from the viewpoints of both dermatology and interface science. Of the surfactants examined, it was found that monosodium monolauryl phosphate (C12MAP1Na) exhibited a considerably higy safety on the human skin because of neutral pH, low skin irritation and small elution amount of natural moisturizing factors such as amino acids from the stratum corneum. These characteristics of C12MAP1Na contribute to low skin roughness. In addition, C12MAP1Na showed excellent foaming and sebum removal properties in comparison with typical anionic surfactants such as alkyl sulfates and soaps.
On the basis of these results, a new type of skin cleanser mainly composed of C12MAP1Na was developed. The striking characteristic of this skin cleanser formula is the stable system which in the fine crystals of C12MAP1Na are homogeneously dispersed with the presence of larger amount of inorganic salt. It was confirmed by the use test that the skin cleanser not only had a good foaming power but gave a good feeling to the skin and relatively fast recovery to casual pH level on the skin after washing face.
Thus, since MAPs were found to be innovative surfactants, it expected that they will be useful for a wider range of application including skin cleansers.
