78 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS tion, and the desire for dryer sprays have required the development of polymers which tolerate greater levels of hydrocarbon propellants than were pre- viously possible. In the design of these polymers, one must consider such factors as choice of monomers used, their ratios and distribution within the backbone, as well as polymer molecular weight and the manner in which it is formulated. These variables not only affect solubility but will also strongly impact on performance parameters such as polymer hardness, humidity resistance, drying time, combing, gloss, adhesion, and shampoo re- movability. Although some of these properties can be mutually exclusive, new polymers are highly hy- drocarbon-tolerant and possess all of the desirable attributes demanded by formulatots addressing today's hair styles. Polysaccharides for personal care applications G. L. Brode, R. L. Kreeger, E. M. Partain, and J. L. Pavlichko, Union Carbide Corporation, P.O. Box 670, Bound Brook, NJ 08805 Amerchol Corp., P.O. Box 4015, Talmadge Rd., Edison, NJ 08818-4051 (J. L. Pavlichko) Hyaluronic acid is an excellent skin conditioner and moisturizer. To improve its substantivity to skin, polyquaterium 24 (QUATRISOFT Polymer LM-200) was developed. Several synthetic routes were explored to develop this hydrophobic modi- fied, cationic polysaccharide. The complexing of QUATRISOFT with hyaluronic acid increases the acid's substantivity to protein (skin) surfaces. This increase was revealed through tritium labeling ex- periments and x-ray photoelectron spectroscopy (ESCA). The use of these two polymers in combina- tion has led to the development of BlOCARE Polymer HA-24. SESSION B THE ROLE OF FRAGRANCE IN PERSONAL CARE PRODUCTS Olfactory mechanism--Base odors and mal- odor control Henri Hoffmann, Hoffmann Associates, 451 Mon- ument Rd., Jacksonville, FL 32225 This presentation will focus on the olfactory mecha- nism and on base odors and malodor control. It will include a review of theories of olfaction and a dis- cussion of the modern approach to the process of olfaction which will include information on five ol- factive systems, the cerebral path of olfactive per- ception and the cerebral imaging of odors. Mention will also be made of olfactive behavior (the language of odors, the olfactive comportment, and olfactive memory), and of perception of odor mixture. The presentation will conclude with a definition of ob- jectionable odors, and a discussion of methods of masking, blending, and counteracting malodor, and the application to consumer products (bleaches, perms & depilatories, protein in shampoos and hair conditioners, soaps, fatty skin products, etc). Lastly the discussion will focus on unfragranced and lightly fragranced products. Solubilization of fragrances Donald L. Courtney, ICI Americas Inc., Wil- mington, Delaware 19897 The art and techniques involved in solubilizing a fragrance into water to form microemulsions are ex- amined from early concepts to current state-of-the- art methods. Commonly used surfactants are re- viewed, and new products are examined for compar- ison. Use of the HLB system is proposed to reduce the level of surfactant required. Consideration of re- quired particle size of emulsion droplets, measure- ment of haze instrumentally, and stability require- ments of solubilized systems are presented. Fragrances and their stability in personal care products Robert L. Raymond, Firmenich, Inc., P.O. Box 5880, Princeton, NJ 08540 Fragrances are an important consumer attribute which can either help or hinder the success of a con- sumer product. Most fragrances are complex mix- tures of synthetics and natural essential oils which can react with many different ingredients contained in personal care formulations, causing significant changes in fragrance and/or product characteristics which can affect consumer acceptability. A number of potential product-fragrance stability problems will be reviewed, with suggestions to the product development chemist on how to avoid or minimize these possible changes. Sensory appeal of fragranced products William S. Cain, John B. Pierce Foundation Labo- ratory, Yale University, 290 Congress Ave., New Haven, CT 06519 Fragrances have appeal at various levels: sensory, aesthetic, and cognitive. In personal care products there is often a delicate balance between seeking aesthetic appeal (i. e., presenting the fragrance as an object of beauty) and seeking cognitive appeal (i.e., conveying a message about the function of a product). Certain fundamental phenomena studied in the sensory laboratory have relevance to achieving this balance. Such phenomena include sensory memory, habituation, masking, and multimodal impact. Although the sensory scientist may not have the ability to design products from the bottom

ABSTRACTS 79 up, he or she may offer ways to explain the complex appeal and acceptance of fragranced products. SESSION C EMERGING TECHNOLOGIES FOR NEW PRODUCT DESIGN Liposomes: Potential application to the skin Norman. Weiner, University of Michigan College of Pharmacy, Ann Arbor, MI 48109 Liposomes recently have received much attention in the search for a more effective means of delivering intrinsically active drugs to their tissue targets. Li- posomes are microscopic vesicles consisting of one or more concentric lipid bilayers enclosing an equal number of aqueous compartments. The attractive- ness of liposomes as drug carriers lies in their abili- ties to encapsulate and physically protect drugs, to selectively concentrate drugs at various body sites, and even to facilitate the transport of some drugs across biological membranes. Liposomes are gener- ally nontoxic and readily metabolized, which adds measurably to their attraction. Recently, there have been a number of reports on the potential applica- bility of liposomes as drug carriers by the topical route. In a recent study, we have shown that lipo- somes themselves do not penetrate intact skin. They do, however, facilitate skin deposition of drugs which tend to associate with liposomal bilayers. The degree of facilitation is dependent on the na- ture of the drug and the lipid composition of the liposome. Liposomal encapsulation of hydrophilic drugs which are encapsulated in the liposome's aqueous compartments retards transport through the skin. Monolayer studies of drug-lipid interac- tions can be used to optimize the formulation with respect to transport properties. Of particular im- portance, we have demonstrated that liposomally encapsulated large polypeptides, but not free drugs, penetrate intact skin and maintain its biological ac- tivity. Liposomes: From theoretical membrane model to cosmetic tool George Strauss, Dept. of Chemistry, Rutgers Uni- versity, P.O. Box 789, Piscataway, NJ 08854 Liposomes have become an important model for studying reactions in biomembranes and simulta- neously have emerged as a vehicle for controlled de- livery of cosmetics, antibiotics, and drugs. Lipo- somes are closed vesicles consisting of one or more concentric lipid bilayer membranes. They are com- posed of polar lipids generally having two alkyl chains of 12 to 18 carbons. Examples include phos- pholipids, such as lecithin, and quaternized am- monium salts with two long-chain alkyls. Lipo- somes resemble biological membranes of cells and organelles: both have selective and limited perme- abilities to water and small molecules, have two-di- mensional fluidity, and can fuse with other mem- branes. Polar and non-polar substances can be in- corporated into the bilayer walls of liposomes or can be trapped in their inner aqueous compartments. Liposomes can be formed by several techniques. These include sonication, injection of alcoholic so- lutions into water, and change in pH. Solutes, such as fatty acids and their esters, steroids, and pro- teins, can be incorporated in the course of forming liposomes by the above techniques. Liposomes can be stabilized in the presence of certain saccharides. Administration of cosmetic or therapeutic sub- stances in liposome-encapsulated form rather than in the free state confers many advantages: un- wanted side reactions are eliminated delivery can, in some cases, be targeted for a specific type of cell or biological structure and a heavy one-time dosage is replaced by continuous delivery over an extended period. A practical approach to the development of mi- croemulsions Barbara H. Munk, Stepan, 22 Frontage Rd., Northfield, IL 60093 A practical and simple three-phase approach to the formulation of microemulsions has been developed. This approach was originally used to develop pesti- cide microemulsions but has been demonstrated to be useful in the formulation of products in other areas. In Phase I, the emulsification and solubility properties of the hydrophobic or "oil" phase with a variety of surfactants and solvents are defined. Promising surfactants and solvents are blended in Phase 2 to identify emulsifier systems which pro- vide the desired physical properties at fixed water and "oil" levels. These emulsifier systems are opti- mized in Phase 3 to produce the final formulation. Ternary phase diagrams are used in Phases 2 and 3 as a tool for quickly evaluating the ability of an emulsifier system to produce a microemulsion of a specified "oil phase." An example of the use of this approach to develop a cosmetic microemulsion will be discussed. Principles of cosmetic delivery systems Joel L. Zatz, Rutgers University College of Phar- macy, P.O. Box 789, Piscataway, NJ 08854 A cosmetic delivery system is a packaged group of ingredients intended for application to the skin. Though such system• may be structurally similar to dermal and transdermal devices used in drug de- livery, this need not be the case. They have several advantages: it is possible to utilize substances