DYNAMIC HAIRSPRAY ANALYSIS 261 I./=2-•-+•rr 4 +2 •-+9•rr 4 +...+2 +(n-1)2•rr 4 q'rr = 2 -•- + (2N- 1 )2 'rrr 4 1 -- 4 P n n'rr r REFERENCES (1) International Hair Science Symposium, Rostock, Germany, September 1996. (2) J.A. Swift, Some simple theoretical considerations on the bending stiffness of human hair, Int. J. Cosmet. Sci., 17, 245-253 (1995). (3) J. A. Swift, Letter to the Editor, J. Cosmet. Sci., 51, 37-38 (2000). (4) J. Jachowicz and K. Yao, Dynamic hairspray analysis. I. Instrumentation and preliminary results, J. Soc. Cosmet. Chem., 47, 73 (1996). (5) J. Jachowicz and K. Yao, Dynamic hairspray analysis. II. Effect of polymer, hair type, and solvent composition, J. Cosmet. Sci. 52, 281 (2001). (6) Den Hartog, Strength of Materials (Dover Publications, New York, 1977).

j. Cosmet. Sci., 53, 263-268 (September/October 2002) Application of a non-invasive method to study the moisturizinD effect of formulations containinD vitamins A or E or ceramide on human skin GISLAINE RICCI LEONARDI, LORENA RIGO GASPAR, and PATRICIA M. B. G. MAIA CAMPOS, Faculty of Health Sciences, Department of Pharmacy, Methodist University of Piracicaba, Piracicaba, S•7o Paulo (G. R.L.), and Faculty of Pharmaceutical Sciences of Ribeir•7o Preto, University of S•7o Paulo, Ribeir•7o Preto, S•7o Paulo (L.R.G., P.M.B.G.M.C.), Brazil. Accepted for publication April 30, 2002. Synopsis Moisturizers containing vitamins A and E as well as ceramides are believed to improve the skin condition by increasing the water content of the stratum corneum. The aim of this research was to evaluate, through the capacitance method (a non-invasive method), the moisturizing effect of an O/W emulsion (non-ionic self-emulsifying base) containing vitamin A palmirate, vitamin E acetate, and ceramide Ill on human skin. The studies were carried out on a group of 40 healthy Caucasian female test subjects between 30 and 45 years of age, using the Corneometer CM 825 PC. Skin measurements were taken from the volunteers at 7 and 30 days after daily use (twice a day) of the tested products. The presence of vitamins A and E or ceramide III did not cause an improvement in the hydration of the stratum corneum, which means that none of those compounds strengthens the hydration effectiveness of the base formulations used, at least at the doses tested. The interpretation of electrical measurement regarding skin moisture should be made with caution thus the results observed in this study show the importance of using different approaches (or methodologies) to verify the performance of the formulas tested. We conclude that, at the low doses typically used in cosmetic formulations, vitamins A and E and ceramide III are not likely to contribute to the hydrating effects of the base moisturizing formulation when assessed by capacitance. INTRODUCTION Vitamins A and E as well as ceramides have been widely used in cosmetic moisturizing products (1-4). The stimulatory effects of vitamin A tend to oppose changes that occur with aging (5). Several studies report the effects of vitamin A palmitate in the epithe- lization of dry and rough skin (5,6). Maia Campos and collaborators evaluated the effects Address all correspondence to Gislaine Ricci Leonardi. 263