116 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS various types of emulsifiers and oils to establish the manner in which they effect the moisture loss from the skin. When this is done perhaps we will be able to develop emulsions which act so as to build up moisture and soften the skin. Here, again, this study is designed as a laboratory test for accurately measuring one specific property of a cosmetic cream or lotion. A great deal of additional study and work will be needed before any clear-cut conclusions can be drawn. The .work to date indicates that many humectants and hand lotions tend to increase the rate at which the skin dries out and suggests that they are not particularly effective in softening the skin REFERENCES (I) Goodman, L. S., and Gilman, A., "The Pharmacological Basis of Therapeutics," New York, The MacMillan Co. (1955), pp. 1017-1019. (2) Blank, I. H., 7. Invest. Dermatol., 18, 433 (1952). (3) Peck, S. M., and Glick, A. W., 7. $oc. Cosmetic Chemists, 7, 530 (1956). (4) Blank, I. H., Proc. $ci. Sec. Toilet Goods dssoc., No. 23, 19 (1955). (5) Rothman, S., "Physiology and Biochemistry of the Skin," Chicage, The University of Chicago Press (1954). (6) Mali, J. W., 7. Invest. Dermatol., 27, 451 (1956). (7) Flesch, P., Proc. $ci. Sec. Toilet Goods dssoc., No. 29, 27 (1958). (8) Blank, I. H., and Shappirio, E. B., 7. Invest. Dermatol., 25, 391 (1955). (9) Flesch, P., and Esoda, E. C. J., Ibid., 28, 5 (1957). (10) Gaul, E., and Underwood, G. B., Ibid., 19, 9 (1952). (11) Powers, D. H., and Fox, C., Proc. $ci. Sec. Toilet Goods dssoc., No. 28, 21 (1957). THE ROLE OF DETERGENTS IN SHAMPOOS By DonALD H. Pow.Rs and CHARL.S Fox* Presented September 17, 1958, International Symposium, Copenhagen, Denmark THE IMPOgTANCE of detergents in shampoos is clearly indicated by the fact that they are used in the great majority of all important shampoos sold in the American market. It has been claimed that they alone are responsible for the growth and acceptance of shampoos to the point where their annual sales are over one hundred and twenty million dollars. It is particularly interesting to note that the formulation of these shampoos depends not only on the detergent as the active ingredient but the addition of conditioners, foam-builders, viscosity builders, delicate fragrances--all are most important in making them cosmetically acceptable. In this paper a study of the detergents alone uncompounded is made to determine what role they play in producing a cosmetically acceptable shampoo. It must be re-emphasized that shampoos are not just cleansers * Warner-Lambert Research Institute, Morris Plains, N.J.

ROLE OF DETERGENTS IN SHAMPOOS 117 and truly cleansing and scouring the skin and hair gives an unacceptable effect. During the past twenty years the emphasis in shampoo advertising has shifted from a preparation that thoroughly cleans the hair to a preparation that leaves the hair fragrant, soft, manageable and lustrous and, inciden- tally, cleans the hair and scalp mildly (1, 2). That the cosmetic industry is approaching an acceptable shampoo is evidenced by the fact that the sale of shampoos has grown to its present size in the past twenty years. This success is not entirely due to chance or sophisticated advertising. Time and again it has been proven--that when a product fulfills a need'--it will usually succeed, even if it costs more than its less acceptable predeces- sor. It is for this reason that aerosol shave creams have made such in- roads into the sale of creams in tubes and jars that home permanents replaced the curling iron that aerosol hair sprays have largely replaced the bottled gum hair sets and that shampoos have replaced the bar of soap. When soft water is available, the bar of soap is ideal for a man's head of hair, but is inconvenient for a woman to use. The need was felt for a preparation that would wet the hair more readily and would lather and give a richer lather faster. Thus, the bar of soap gave way to liquid potash soap preparations. The liquid soap shampoos had a limited success but it was obvious that further product improvement was needed. Soap sham- poos are fine in soft water and, when formulated with the proper ratio of C•2 to C•8 fatty acids, they give a rich, wet, dense, copious lather, which rinses easily and leaves the hair lustrous and manageable. In hard water areas the latherability of the soap shampoo decreases and, what is much more serious, calcium and magnesium soaps are precipitated onto the hair, leaving a film of insoluble lime soaps. In extremely hard water areas the lime soap precipitated on the hair makes combability dif- ficult, leaves the hair tacky and may actually lead to dirtier looking hair. Women would not tolerate these results and corrected this condition by following the soap shampoo with a lemon or vinegar rinse. These acid rinses helped to remove the hard water soaps, leaving the hair more nearly lustrous. It is not surprising, then, that, with the advent of synthetic detergents, the major growth and development of the shampoo market occurred. Synthetics were a group of water-soluble materials that lathered well in hard water and did not leave a heavy insoluble precipitate on the hair. As experimentation proceeded with the synthetic detergents, it became obvious that shampoos with good consumer acceptance required something more than a colored, perfumed solution of a detergent. In many instances the synthetic detergents do not lather well in the presence of sebum--the natural oil of the hair and scalp--hair dressings, sweat, and wave set residues. They also require the addition of lather boosters to enhance the