ABSTRACTS 403 Free formaldehyde in anionic shampoos Marvin Rosen, Ph.D., and Andrew McFarland, Ph.D., Glyco Inc., P.O. Box 3187, Williamsport, PA 17701 An analytical method has been developed for determining the free formaldehyde content of anionic shampoos, with and without protein, with formaldehyde derived preservatives. The preserva- tives studied were 1,3-dimethylol-5, 5-dimethylhy- dantoin, methane bis [N,N'-(5-ureido-2, 4-diketo- tetrahydroimidazole)-N,N'-dimethylol], N-(hydrox- ymethyl)-N-(1,3-dihydroxymethyl-2, 5-dioxo-4-imi- dazolidinyl)-N'-(hydroxymethyl) urea, cis-l-(3-chlo- roallyl)-3,5,7-triaza- 1-azoniaadamantane chloride, and formaldehyde. The method is based upon establishing an equilib- rium of formaldehyde between the sample, the vapor phase, and an aqueous trapping solution. The trapping solution is measured colorimetrically for free formaldehyde at 513 nanometers using phenyl- hydrazine hydrochloride. Studies were conducted at temperatures of 23øC and 60øC at concentrations of 0.1-0.8% contained preservative. The order of formaldehyde release found was methane his [N,N'-(5-ureido-2, 4-diketotetra- hydroimidazole)-N,N'-dimethylol] 1,3-dimeth- ylol-5, 5-dimethylhydantoin N-(hydroxymethyl)- N-(1,3-dihydroxymethyl-2, 5-dioxo-4-imidazolidi- nyl)-N'-(hydroxymethyl) urea cis-l-(3-chloroal- lyl)-3,5,7-triaza-l-azoniaadamantane chloride. The amount of free formaldehyde released was the same at 23 ø and 60øC. Protein reduced the concentration of free formaldehyde present. In the absence of protein, the ratio of free to total formaldehyde increased with decreasing preserva- tive concentration. SCIENTIFIC SESSION III FORMULATING COSMETIC AEROSOLS IN THE 1980'S Aerosol hair care preparations Morris J. Root, Morris J. Root Associates, 900 Green Bay Road, Highland Park, IL 60035 The advent of the aerosol package stimulated the development of not only new products, but new raw materials for use in them. In particular, aerosol hair sprays spawned a host of synthetic resins to replace and supplement the now almost obsolete shellac originally used. As a result of this develop- ment, there are now in the aerosol spray hair care category not only hair fixative sprays, but lusteriz- ers, conditioners, and setting lotions. In the aerosol foam hair care grouping are waving lotions, hair dyes, shampoos, conditioners, and setting lotions. One must also mention aerosol foam depilatories, which might be labelled a "hair control" rather than a "hair care" product. These aerosol preparations are not used solely by women, but have been adopted by men as well. This is especially true of hair fixative sprays which have, to some extent, replaced men's hair dressings packaged in bottles and tubes. The most recent development is the introduction of the "conditioner and styling mousses" which promise to become another major hair care prod- uct. Fragrance in aerosol products Montfort A. Johnsen, Ph.D., Peterson/Puritan, Inc., Hegeler Lane, Danville, IL 61832 Aerosol products often contain water ranging in pH from 3 to 13. Others are hydroalcoholic, and sometimes contain active ingredients such as phe- nolic or quaternary derivatives. Using the wrong perfume with any of these compositions may cause container corrosion, the development of strange odors and colors, or other unwanted effects. With aerosols containing high levels of isobutane or propane propellants, certain ingredients in the fra- grance blend may slowly precipitate. Some prod- ucts require fragrance to cover chemical odors of other ingredients, while others are used to mask or destroy chemical odors in the home. The degree of atomization must be considered, since a finely dispersed spray will cause significant portions of all the perfume notes to be presented to the nose at the same time, unlike the non-aerosol preparations, where the essential oils evaporate in successive stages. Finally, the amount of fragrance in aerosols ranges from about 0.03% in the "unscented" prod- ucts, past an average value of about 0.18% to as high as 60% for one unusual item. At high levels fragrance oils can cause problems with valve gas- kets. Careful research is needed when developing aerosols containing any amount of fragrance ingre- dients. New era in aerosol propellants John J. Daly, Ph.D., Freon Products Division, Du Pont Company, Chestnut Run, Wilmington, DE 19898 A new line of aerosol propellants has recently been introduced. The four products include: (1) dimethyl ether (2) chlorodifiuoromethane (3) 1,1-difiuoro- ethane and (4) 1,1,1-chlorodifiuoreoethane. The physical, chemical, and toxicological properties of these propellants will be described. Interrelation-

404 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ships of concentration, vapor pressure, flammabili- ty, and solubility will be explained, and formula- tions specifically directed to the use of these propellants in personal and other products pre- sented. SOCIETY OF COSMETIC CHEMISTS FRONTIERS OF SCIENCE LECTURE Theory in chemistry Roald Hoffmann, Ph.D., Department of Chemistry, Cornell University, Ithaca, NY 14853 The motion of the electrons in a molecule is behind every physical, chemical, and biological property of a molecule. The most easily perturbed, the least tightly bound electrons are most important in determining these properties. Such electrons move in "frontier" orbitals. An account of the frontier orbitals and their role in determining the geometry of molecules and the course of chemical reactions will be given. SCIENTIFIC SESSION IV Percutaneous transport of antihistamines Lawrence H. Block, Ph.D., and Samir K. Gupta, School of Pharmacy, Duquesne University, Pitts- burgh, PA 15282 Percutaneous penetration in vitro was followed temporally for selected antihistamines: chlorpheni- famine, diphenhydramine, pheniramine, and pyri- lamine. For these compounds, derreal transport was a function of solute lipophilicity. The permeability constants, diffusion constants, transport fluxes, and computed time lags were functions of the solute octanol/buffer partition coefficients. The use of guinea pig skin and rat skin preparations in these studies led to additional observations: (1) epidermal separation was achieved readily with ammonium thiocyanate (2) derreal transport was comparable to that achieved with skin prepared with ammo- nium hydroxide or stripping and (3) guinea pig skin preparations yielded results more consistent than rat skin preparations. A review of silicon chemistry for the cosmetic chemist Michael S. Starch, Dow Corning Corp., 2200 W. Salzburg, ffC40B00, Midland, MI 48640 Since their first commercial skin care application in the early 1950's, silicones have become known to the personal care formulatot for their unique chem- ical and physical properties. These properties have led to applications in virtually every class of per- sonal care products, including antiperspirants, cos- metics, hair care products, and skin care products. In order to explain the properties of silicones, a review of silicon chemistry will be presented. The similarities and differences between carbon and silicon chemistry will be discussed, and the unusual properties of siloxane polymers will be explained in terms of the differences between siloxane bonds and the carbon-carbon bonds in organic polymers. Many of the important physical characteristics of silicones will be shown to be a direct consequence of the peculiarities of siloxane chemistry. A brief review of the industrial synthesis of silicones will be given, with special emphasis on silicones of interest to cosmetic chemists. Also, the chemical and physical properties of silicones will be related to potential benefits in a variety of product catego- ries. Low-energy emulsifications. Part VI: applica- tions in high-solids emulsions T.J. Lin, Ph.D., and Y. F. Shen, 628 Enchanted Way, Pacific Palisades, CA 90272 Low-energy emulsification (LEE) is a technique by which thermal and mechanical energies are selec- tively applied to only a portion of the emulsified components at certain emulsification stages. By applying far less energy than the conventional hot process, LEE can not only reduce energy costs, but can also significantly reduce cooling time and increase production efficiency. Frequently, the use of a refrigerated system can be completely elimi- nated through the application of LEE in commer- cial processing of cosmetic and pharmaceutical emulsions. Although LEE has proven to be very useful in processing a wide range of emulsions, it has been difficult in the past to apply it to O/W emulsions having solid contents greater than 30% because of the potential phase inversion problems. Phase inversion of the concentrate often leads to poor emulsification and poor stability. By using a new technique of double withholding, LEE can success- fully process a wide range of relatively high solids emulsions while avoiding the common phase inver- sion problems. The athymic nude mouse grafted with human skin as a model for evaluation of radiolabeled cosmetic ingredients Robert V. Petersen, Ph.D., College of Pharmacy, University of Utah, Salt Lake City, UT 84112 During recent years considerable attention has been directed toward transdermal delivery as a means of administering biologically active chemicals to the body. As a result, a large body of information has