58 JOURNAL OF COSMETIC SCIENCE exposure time, lack of a 'water rinse', and the solution properties of soap and synthetic detergents. Under static non-shear conditions, soap, unlike synthetic detergents (as represented by the syndet bar in this study), can form higher-ordered gel-like structures. We suggest this physical form restricts the bio-availability of irritant components which manifests as a Na-soap Skin Culture Forearm Test Test IL-lc• MTT Index Index Dryness Redness being potentially more 'mild' than a syndet in the in vitro assay. Under in vitro conditions in which the test matedhal is briefly applied and rinsed off with water (typical for real personal cleanser use), the data are more consistent with real usage, i.e., Na-soaps Na Soap 5% Soln 23.5 a 0.6 a 10% Soln 19.6 a 0.5 a TEA Soap 10% Soln 10.0 b 1.0 Syndet 10% Soln 13.3 b 0.9 2.30 a 1.58 a 1.25 b 0.82 b 1.38 b 0.88 b are potentially more irritating than syndets (Frosch, 1982, and Sharko et al., 1991). Interestingly, using this modified in vitro procedure there can be an increase of IL-l•t with little to no effect on culture viability. We believe this restricted effect on IL-l•z to the exclusion of the toxicity marker, MTT, may allow this method to discriminate between relatively mild contact irritants. At high concentrations (as observed with Na-soap), IL-1 excretion may be compromised by effects on tissue viability, however. References: Dillarstone, A. and Paye, M. (1993). Antagonism in concentrated surfactant systems. Contact Dermatitis 28, 198. Emery, B.E. and Edwards, L.D. (1940). The pharmacology of soaps. The irritant action of soaps on human skin. J. Am. Pharm. Assoc. 29, 251-254. Frosch, P.J. (1982). Irritancy of soap and detergent bars, in: Principals of Cosmetics for The Dermatologist. P. Frost and S.N. Horwitz (eds.) C.V. Mosby Co: St. Louis, pp. 5-12. Gay, R., Swiderek, M., Nelson, D., and Ernesti, A. (1992). The living skin equivalent as a model in vitro for ranking the toxic potential ofdermal irritants. Toxicol. In Vitro 6, 303-315. Sharko, P.T., Murahata, R.I., Leyden, J.J., and Grove, G.L. (1991). Arm wash with instrumentation evaluation. A sensitive technique for differentiating the irritation potential of personal washing products. J. Derreal Clin. Eval. Soc. 2, 19-27. Smeenk, G. (1969). The influence of detergents on the skin (a clinical and biochemical study). Arch Klin. Exp. Dermatol. 235, 180-191.

PREPRINTS OF THE 1998 ANNUAL SCIENTIFIC MEETING 59 INVESTIGATION OF CONDITIONING POLYMERS FOR HAIR STYLING Peter Hossel, Ph.D. BASF AG, Ludwigshafen (Germany) Introduction Cationic polymers are impotlant components of haft-care products such as shampoos, mousses, hair treaUnents, rinses and gels. Most of these products are quaternmy substances that, because of their cationic nature, have a high affinity to the surface of the hair, which is negatively charged. The most important function of these substances, the protection of the haft surface and the improvement of wet- combability are a result of their substantivity, i.e. their ability to adsorb to the haft. In addition to practical tests that are conducted in the haintressing salon, quick and reproducible laboratory tests are needed to assess cationic polymers and their properties on the hair. We have tested the major quaternary polymers individually and in the combinations found in the markel. Because these cationic polymers have different chemical structures, their technical properties and fields of application can differ quite considerably. Many of the practical properties of these polymers can be determined and compared using objective test methods, without having to resort to costly consumer and salon tests. Objective of the study The present study concentrates on a polyelectrolyte fitration, an analytical method for assessing the adsorption of cationic polymers to the haft, and correlating this with their charge density. Another purpose of this paper is to present tests for such practical properties of styling products as stiffness, combing force and lack. Materials and method The following commercially available cationic polymers were investigated: Polyquatemium-4 and Polyquatemium-10 (quaternized cellulose), Polyquatemium-6 (polydiallyldi- methyl-ammonium chloride), Polyquaternium-7 (diallyldimethylanunonium chloride/ acrylamide copolymer), Polyquatemium-11 (vinylpyrrolidonedquatemized dimethylaminoethylmethacrylate copolymer), Polyquaternium-16 (vinylpyrrolidoned vinylimidazolium chloride (VI) copolymers) and Polyquaternium-46 (vinylcaprolactam/vinylpyrrolidone/vinylimidazolium methylsuffate). The charge density (cationic activity) of the polymers was determined by means of a Type 90 pho- toelectric tiwator developed at BASF AG •. In this method, the cationic polymer is titrated against potassium polyvinyl surfate to yield a polymer-polymer complex. When the entire cationic polymer lma been complexed, the excess polassium polyvinyl sadfate reacts with the toluidine blue O indica- tor, changing its colour from blue to pink. The endpoint was determined with a special photometer with one red and one green diode that match the absorption spectrum of the indicator. This dual beam method ensures that any turbidity due to the polymer-polymer complex does not obscure the end- Dark brown caucasian hair swatches were used to determine the adsorption of the cationic polymers. The adsorption was determined from the decrease in polymer concentration in the solution (200 mgtl) after 10 min a. Wet combing force measurements were performed on medium bleached swatches of caucasian hair and the stiffaess tests a on virgin dark caucasian hair by m•nn of an Easy-Test 86802/E tensile tester. The tack of the polymer films was determined with a special lack-testing ilLqtrtlment 4. Results and Discussion Depending on the type of polymer, •he quantity adsorbed varied between I and 5 mg/g haft. Fig. 1 shows that there is a direct correlation between the charge density of the polymer and the q,•ntity adsorbed. The higher the charge density, the less polymer is adsorbed on the hair. Evidently, the lower the charge density of the polymer, the greater the quantity requingd to neutralize the negatively charged surface of the hair. The decrease in combing force is also a function of the positive charge (Fig. 2). The higher the charge density, the greater the conditioning effect and the reduction in resinante to combing