370 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS bolic and pathologic states. Gas chromatography with element specific detectors and gas chromatography/mass spectrometry have been employed to analyze the complex oral odors from several groups of subjects. The breath air and saliva of subjects with periodontal disease emits volatiles more rapidly than those subjects with healthy mouths. Several volatile malodorous compounds appear to be diagnostic of the active disease state. Prevailing biochemical conditions in the oral cavity during ovulation and menstruation favor accelerated production of volatiles. Several constituents show cyclic changes predictive of these important times. Novel instrumental methods for odor detec- tion Annette Lovett, Ph.D., SCIEX, 55 Glen Cameron Road, Thornhill, Ontario, Canada L3T 1P2. The analysis of volatiles presents unique problems to the analytical chemist. Ideally, what is required is a device which has the specificity and ease of sample introduction comparable to that of the nose, but without its memory effects, unpredictable response characteristics, and subjectivity in data analysis. A novel mass spectrometer, the TAGA 6000 triple quadrupole system, with a unique atmo- spheric pressure chemical ionization (APCI) ion source, has the ability to detect and characterize volatile chemicals in ambient air in real time. Chemicals are introduced into the ion source using air or other suitable carrier gas, without the need for a vacuum interface, permitting the direct sampling of a variety of environments. The TAGA 6000 APCI/MS/MS system has been used to analyze the headspace vapours of a number of naturally occur- ring and synthetically formulated fragrance and flavour mixtures without prior extraction, precon- centration, or chromatography. This system is par- ticularly suited for monitoring concentration changes of specific targeted compounds in cos- metic preparations or on the skin. Odor perception and masking Clair Murphy, Ph.D., San Diego State University, San Diego, CA 92182. Perceived odor intensity increases with increases in stimulus concentration, although intensity in- creases at a much slower rate. Increasing the odorant concentration ten-fold may produce only a two-fold or four-fold increase in perceived odor magnitude. When odorants are mixed, the per- ceived magnitude of the mixture will generally be less intense than the sum of the unmixed compo- nents. Often the mixture will be less intense than the stronger component smelled alone. These sup- pressive effects are magnified when the odorant has a trigeminal (irritating, cooling, or warming) impact or note. In these cases, a strong trigeminal sensation can completely mask an olfactory sensation. The potential for masking malodors with trigeminal sensations is obvious. A more complex form of masking takes place when a pleasing odor is generated by assimilating a malodor into an odor complex which includes the malodor as one of its notes. STRUCTURING OF COSMETICS Principles of applied rheology Mike R. Rosen, Ph.D., Union Carbide Corp., Old Saw Mill River Road, Tarrytown, NY 10591. The purpose of this paper is to review and update applied theology, to expand the awareness of cosmetic scientists in rheological fundamentals and their successful application in industry. A further purpose is to empower those interested in enthusi- astically embracing the powerful rheological method for cosmetic product design, characteriza- tion, and control. Specifically, this paper covers the definition of viscosity and a description of New- tonian and non-Newtonian behavior. Methods for describing different types of flow behavior are covered, including both qualitative and quantitative aspects. Brief mention is given to basic types of instrumentation and, finally, consideration is given to the various ways a liquid may be thickened. The stability and rheological properties of particulate dispersions Geoffrey D. Parfitt, Ph.D., Carnegie-Mellon Uni- versity, Pittsburgh, PA 15213. A variety of different theological behaviors has been demonstrated for dispersions of solid colloi- dal particles in liquid media at high particle volume concentration. These may be time independent (plastic, pseudoplastic, and dilatant), or time depen- dent (thixotropic), and all are related in some way to the state of dispersion of the particles. Systems that are stable to flocculation may not be stable to separation by gravity sedimentation a degree of fiocculation might be desirable to prevent the latter, thus leading to flow behavior characteristic of the structure of the system. Interactions between particles depend on the nature of the solid-liquid interface, and stability to flocculation is considered in terms of either the particle charge or the presence of an absorbed polymer layer. Charge and steric stabilization are discussed, as well as relevance to the rheology of concentrated dispersions of pig- ments and fillers in aqueous and non-aqueous media.

ABSTRACTS 371 On the rheology of foams and highly concen- trated emulsions H.M. Princen, Ph.D., Exxon Research and Engi- neering Company, P.O. Box 45, Linden, NJ 07036. Expressions are derived for certain theological properties, such as the stress vs. strain relationship, yield stress and shear modulus, of monodisperse foams and highly concentrated emulsions for the model of infinitely long cylindrical drops (or bub- bles). The variables considered are the volume fraction of the dispersed phase, the drop radi-us, the interfacial tension, the thickness of the films sepa- rating adjacent drops, and the films' associated contact angle. Both the yield stress and the shear modulus are proportional to the interfacial tension and inversely proportional to the drop radius. The yield stress increases sharply with increasing vol- ume fraction, while the shear modulus varies as its square ro, ot. The effect of a finite contact angle, 0, is to decrease the shear modulus and in most cases, to increase the yield stress. Finally, the effect of a finite film thickness is always to increase both the yield stress and the shear modulus. Real emulsions and foams are expected to behave similarly, at least in a qualitative sense. Experimental evidence is provided. The application of rheology to cosmetic and pharmaceutical systems Nagin K. Patel, Ph.D., Anthony J. Cutie, Ph.D., Arnold and Marie Schwartz College of Pharmacy and Health Sciences, 75 DeKalb Avenue, Brooklyn, NY 11201. The cosmetic and pharmaceutical industry has recognized the importance of rheological assess- ments and product characterizations in solving some of the formulation problems (e.g., product texture, flow characteristics, and physical stability associated with suspensions, emulsions, and semi- solids). This paper examines some of the method- ologies and instrumentation presently used within these industries to characterize the structure of these rather complex heterogenous systems. The usefulness of rheograms is demonstrated in terms of formulating new products or reformulating existing products. Rheograms illustrating such sub- jects as the effect of various cellulose derivatives added, the effects of aging, and the addition of viscosity modifiers are presented, as well as specific delivery systems including methylcellulose gels, antacid suspensions, creams, and semi-solids lip- sticks. The application of such data necessary to the formulation design, scale-up operation, stability, texture, and final use of the cosmetic pharmaceuti- cal product is illustrated. SPECIAL TOPICS IN METHODOLOGY Skin irritation and DNA damaging qualities of cosmetics Shigeru Yamamoto, M.D., TBC-America, 606 N. Larchmont Blvd., Los Angeles, CA 90004. In Japan, reports of injuries due to cosmetics in 1981 markedly increased 162% from the previous year. The cosmetics that were the cause of the complaints were mostly products of major manu- facturers that had been thoroughly tested. Despite the fact that the cause is sometimes the consumer's fault, the number of complaints indicate that the cosmetics are a contributing cause. If there is a causal effect from the products, it seems clear that present skin irritation tests are not sufficient for determining the skin irritation properties of cos- metics, and that some problems relating to skin irritation are undetected. During dermatological diagnosis of patients having skin irritations caused by contact with cosmetics, it was found that cosmetics with a high irritation potential very often also caused damage to the DNA of Bacillus coli. Those cosmetics showing strong reactions in patch tests had the most DNA-damaging properties. Translating this finding to cosmetic formulation suggests that the aim should be to make cosmetics with low DNA-damaging properties. This means that cosmetics with less irritation potential can be made more economically, easily, and quickly than before. The DNA-damage test should be incorpo- rated into cosmetic irritation test protocols as a more effective method than the patch tests and animal studies used at present. ,'.vaiuaun• cleaning toothbrush designs and textures Samuel L. Yankell, Ph.D., P. Nygaard-Ostby, D.D.S., University of Pennsylvania School of Den- tal Medicine, 4001 Spruce Street, Philadelphia, PA 19104. Cleanliness of the oral cavity is imperative for cosmetic appearance and dental health, and the toothbrush is the main aid for this purpose. There is a need for better laboratory and clinical assessment of toothbrush efficiency. The purpose of this study is to evaluate the efficiency of toothbrushes of different designs and textures. An apparatus was utilized that simulates horizontal and vertical brush- ing movements at various pressures on anterior and posterior shaped teeth. Cleaning efficiency was scored by measuring the accessibility between the