WATER-HOLDING CAPACITY OF MOISTURIZERS 287 minutes and three hours after application of agents, and 10% urea cream was second in rank. For the water-holding capacity aspect, at five minutes after application 10% urea cream was the most efficient agent. It sustained a high water content, which declined slowly. At the same time, pH5-Eucerin seemed to drop faster than the rest, but at the end there were no differences among all agents in the water-content aspect. When compared to three hours after application, the water-holding capacity of pH5-Eucerin declined at nearly the same rate after five minutes observation. On the other hand, other agents showed lower water-holding capacity than pH5-Eucerin. We concluded that pH5-Eucerin is more effective than other agents because 1. The conductance of the prehydration state of pH5-Eucerin is higher than others at observation both five minutes and three hours after application. This reflects the higher water content on the skin surface. 2. pH5-Eucerin can obtain highest hygroscopicity at observation both five minutes and three hours after application. 3. For the water-holding capacity aspect, pH5-Eucerin obtains nearly the same rate of decrement at observation five minutes and three hours after application. This means that pH5-Eucerin still has high stability after three hours application. Among the institute formulas, 10% urea cream was the most effective agent, but urea is one of the popular agents used in commercial preparation, and we feel that it is worthwhile to prescribe it for patients with pathological dry skin conditions (19). ACKNOWLEDGMENTS We would like to thank all of the staff in the photobiology unit of the Institute of Dermatology, who helped us to carry out the testing procedures the volunteers the pharmaceutical unit of the Institute of Dermatology, which prepared the testing agents and the staff of the BDF Company who supplied PH5-Eucerin and did the computer analysis. REFERENCES (1) I. H. Blank, Further observation on factors which influence the water content of the stratum corneum, J. Invest. Dermatol., 21, 259-269 (1953). (2) A.M. Kligman, "The Biology of the Stratum Corneum," in The Epidermis, W. Montagna and W. C. Lobitz, Eds. (Academic Press, New York, 1964), pp. 387-433. (3) I. H. Blank, Factors which influence the water content of the stratum corneum, J. Invest. Dermatol., 18, 433-440 (1952). (4) O. T. Jacobi, About the mechanism of moisture regulation in the horney layer of the skin, Proc. Sci. Sect. Toilet Goo& Assoc., 31, 22-24 (1959). (5) P.M. Elias, Lipids and the epidermal permeability barrier, Arch. Dermatol. Res., 270, 95-117 (1981). (6) C. W. Blichmann, J. Serup, and A. Winther, Effects of single application of the moisturizer: Evaporation of emulsion water, skin surface temperature, electrical conductance, electrical capaci- tance, and skin surface (emulsion) lipids, Acta. Derre. Venereol. (Stockh.), 69, 327-330 (1989). (7) H. Tagami, Y. Kanamaru and K. Inoue, et al., Water sorption-desorption test of the skin in vivo for functional assessment of the stratum corneum, J. Invest. Dermatol., 78, 425-428 (1982). (8) J. L. Leveque, Physical methods for skin investigation, Int. J. Dermatol., 22, 368-375 (1983). (9) J. L. Leveque and J.de Rigal, Impedance methods for studying skin moisturization, J. Soc. Cosmet. Chem., 34, 419-428 (1983).

288 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) A. J. Quattrone and K. Laden, Physical techniques for assessing skin moisturization, J. Sac. Cosmet. Chem., 27, 607-623 (1976). O. R. Potts, Stratum corneum hydration: Experimental techniques and interpretation of results, J. Sac. Cosmet. Chem., 37, 9-33 (1986). R. L. Anderson, J. M. Cassidy, J. R. Hansen, and W. Yellin, Hydration of stratum corneum, Biapalymers, 12, 2789-2802 (1973). E. F. E. Cooper and B. F. Van Duzee, Diffusion theory analysis of transepidermal water loss through occlusive films, J. Sac. Cosmet. Chem., 27, 555-558 (1976). O. K. F. Jacobi, Nature of cosmetic films on the skin, J. Sac. Cosmet. Chem., 18, 149-160 (1967). R. L. G. Rietschel, A skin moisturization assay, J. Sac. Cosmet. Chem., 30, 369-373 (1979). M. M. H. Rieger and D. E. Deem, Skin moisturizers. II. The effects of cosmetic ingredients on human stratum corneum, J. Soc. Cosmet. Chem., 25, 253-262 (1974). L. M. Lieb, R. A. Nash, J. R. Matias, and N. Orentreich, A new in vitro method for transepidermal water loss: A possible method for moisturizer evaluation, J. Sac. Cosmet. Chem., 39, 107-119 (1988). M. Loden and M. Lindberg, The influence of a single application of different moisturizers on the skin capacitance, Acta. Derm. Venereal. (Stackh.), 71, 79-82 (1991). A. Frithz, Investigation of cortesal, a hydrocortisone cream and its water-retaining cream base in the treatment of xerotic skin and dry eczemas, Curr. Ther. Res., 33, 930-935 (1983).