2000 ANNUAL SCIENTIFIC MEETING 151 STRUCTURE/ACTIVITY RELATIONSHIP IN COSMETIC RAW MATERIAL: TAILOR-MADE NATURAL BLENDS Luigi Rigano, Ph.D. and R. Trenti Rigano Research Laboratories, Milan, Italy The research of new substances is often affected by industrial criteria, such as the ease of chemical synthesis, cost of basic raw materials, reproducibility and presence of impurity, as well as by the investments required by the current laws in order to ensure appropriate safety standards. Natural resources Industrial research has increasingly tended to develop projects, which make sensible use of the existing resources and optimize the blends of known substances of natural origin, where possible This is due to a number of reasons, such as the uncertain prospects of animal-testing, the necessity of making considerable investments when researching new molecules, and the doubt that the proliferation of new substances is inevitably causing the research on functionality of known molecules to lose importance These new strategies can prevent exorbitant financial costs, allow the use of easily reproducible substances at low energy cost, and create special blends whose innovation is represented by the choice and the balanced use of the molecules rather than their structure itself ß New selected blends Many examples of this trend could be given Our study dealt with the original blend of the Meadowfoam Seed Oil, viscous oil extracted from Limnanthes Alba seeds, and Shea Butter phospholipids, commercially named Fancol VB (INC1 name: Limnanthes Alba, Butyrospermum Parkii) initially aimed at implementing the basic absorption properties of lanolin This association brought to a special blend with new properties, with enhanced performances compared to the individual components. We studied in detail its properties in the preparation and stabilization of emulsions and its sensorial performance in order to identify the main possible applications in cosmetics ß Main properties From the preliminary evaluations carried out in order to check to which extent much the compounding hypothesis was confirmed, Fancol VB resulted to be an absorption base, a W/O co- emulsifier and a O/W emulsions stabilizer, a good pigments wetting agent with emollient, super-farting and make-up removing properties. Its capability to substitute lanolin derivatives is made evident by this set of properties and has been confirmed by some experimental applications ß Natural absorption base and W/O co-emulsifier Simple emulsions of Fancol VB (15-20- 25-30-40-50-75%) with water gave decreasing viscosity at the higher water amounts, while pH was not measurable This type of behavior is typical of W/O emulsions and very similar to what is observed with lanolin oil. ß Pigments dispersion power Uncoated mineral pigments and organic lakes were easily dispersed into our oily blend. Powder concentrations that could be reached in order to get fluid suspensions were around 60-65 % of mineral pigments into oil, while the traditionally used castor oil, the most common dispersing agent for pigments used in make-up, may reach 40 -45 % maximum suspended powders. Moreover, lakes may be dispersed at amounts that are about the double (45-50%) of what can be obtained when dispersed in castor oil predispersions of pigments in fluid vehicle can so be easily obtained

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