152 JOURNAL OF COSMETIC SCIENCE Influence on foam volume in a tensioactive blend Considering that polarity makes molecular orientation possible and foams are stabilized by means of systems of orientated molecules, these properties was successfully exploited to achieve stable-foam products. At 2%, foam volume and foam stability of a traditional detergent blend has increased by more than 10 %, while higher percentages did not influence the foam behavior but had noticeable effects on the skin feel of the formulations ß Sensory characteristics After checking the emulsifying and co-emulsifying properties, the structure of the molecules involved was considered It was found that the loose structure of the lipids allowed the achievement of a non-tacky emollient feel as well as the lipids polarity allowed easy emulsification by polymeric emulsifiers• The after-feel of emulsions depends also on the structure of the oils The feel is silky when the spreading properties and the bonds of emulsified oils with surface keratin are stronger than the intermolecular attractions in the oils Formulations Moreover, the polarity of the involved molecules and the solvent power over lipids lead to alternative approach in designing new formulations for removing the make-up. These formulations act upon the proteins/waxes/horny layer bonds and do not use surfactants or emulsifiers Examples of formulations will be given and commented during the presentation. In conclusion, in-depth research of known substances may allow making the most of the distinctive features of their molecules, such as form, structure, polarity and its interrelations

2000 ANNUAL SCIENTIFIC MEETING 153 SURFACTIN SODIUM SALT: AN EXCELLENT BIO-SURFACTANT FOR COSMETICS Tadashi Yoneda', Toshi Tsuzuki l, Eiji Ogata 2 and Yuichi Fusyo 3 •Showa Denko K.K. Central Research Laboratory, Chiba, Japan 2Showa Denko K.K. Specialty Chemicals Division, Kanagawa, Japan JShowa Denko America Inc., New York Introduction Suffactin, one of the most powerful suffactants, was fiest isolated from the culture broth of sevcral strains of Bacillus subtills in 1968(1) and the structure was determined (2,3,4,5). Since, many researches have been reported that such kinds of microorganisms secrete suffactin and it has good potential as a surfactant of special purposes. However, there has been little successful application to industry. The reason was that the productivity of surfactin of the microorganisms was too low to supply it to the market at a reasonable cosl. We have worked around this unique bio-surfactant for several years, and have successfully improved the microorganism and established a production method of surfactin sodium salt with a remarkably high yield. And we have also found its various excellent properties as a surfactant. With such a strong surface activity, we believe, it exhibits an outstanding possibility in various aspects for application to industhai use such as cosmetics, skin-care products, pharmaceuticals and general washing detergents. In this presentation, those properties of surfactin are reported with data including emulsion stability and low skin irritation. Experimental Materials. Surfactin sodiron salt was produced by fermentation of B. subtilis and purified in our laboratory. Human cultured model skin was purchased from Gunze. All other reagents were purchased from domestic suppliers. Male rabbits, aged 8-9weeks, were employed for primary skin irritation examination. Surface activity. Surfactants were dissolved in water and surface activity was measured by the plate method using automatic surface activity meter CBVP-Z (Kyowa kaimen kagaku) at room temperature. Prtmary skm trrttation m rabbtts. Surlactants were dissolved in water_ Each substance was closed-patched on the skin of the rabbits for 24 hours, and the skin was observed after 24, 48, 72 hours and 4, 5, 7, 10, 14 days. The erythema and edema observed were scored by the standards of Draze's method. Figure 1 A cheimcal stn•cture of surfacnn Z•60 ,o_ _.• 40 u) 20 I I I I I '-• Surfaorta Na -{•]- Tnto n X100 -- -• SLG -0- SDS r-'c _ ß 3•M I I I I i o o.o(3ol o OOl O.Ol o.1 1 lO lOO Conc•tradon (raM) Results and discussion Structure of Surfactin molecule. The typical chemical Figure 2. A comparison of the surface activity structure of surfactin is shown in Figure 1. It has a hydrophilic peptide-ring consisted of seven amino acids. L-glutamic acid and L-aspertic acid have •'o carboxyl