(1) (2) (3) (4) (5) (6) (7) (s) (9) (10) (11) DIMETHYL SULFOXIDE 127 References Stoughton, R. B., and Fritsch, W., Influence of dimethylsulfoxide (DMSO) on human percutaneous absorption, Arch. Derrnatol., 90, 512 (1964). Rosenbaum, E. E., et al., Dimethyl sulfoxide in musculoskeletal disorders, J. Am. Med. Assoc., 192, 109 (1965). Kligman, A.M., Topical pharmacology and toxicology of dimethyl sulfoxide--Part 1, ibid., 19:t, 796 (1965). Kligman, A.M., Dimethyl sulfoxide--Part 2, Ibid., 19:t, 923 (1965). Stone, O. J., Thiabendazole in dimethyl sulfoxide for Tinea Nigra Palmaris, Arch. Derrnatol., 9:t, 241 (1966). Leake, C. D., Dimethyl sulfoxidc, Science, 152, 1646 (1966). Sweeney, T. M., et al., The effect of dimethyl sulfoxide on the epidermal water barrier, J. Invest. Derrnatol., 46, 300 (1966). Ainsworth, M., Methods for measuring percutaneous absorption, J. Soc. Cosmetic Chemists, 11, 69 (1960). Kligman, A.M., The biology of the stratum corneum, in Montagna, W. and Lobitz, W. C., Jr., The Epidermis, Academic Press, N.Y., 1964, pp. 387-433. Vinson, L. J., et al., The nature of the epidermal barrier and some factors influencing skin permeability, Toxicol. Appl. Pharrnacol., 7, 7 (1965). Trcgear, R. T., The permeability of mammalian skin to ions, J. Invest. Derrnatol., 46, 16 (1966).

J. Soc. Cosmetic Chemists, 19, 129-136 (Feb. 5, 1968) A Titration Method for Determination of the HLB's of Emulsifiers the JAMES J. MIDDLETON, B.A., M.B.A.* Presented May •, 1967, New York City Synopsis--A titration method for determining HLB's, particularly of emulsifiers, is pre- sented. This is a color-migration procedure, similar to the Epton method for determining anionics or cationits. Parameters of variables are discussed, especially as to the control of errors and their magnitude for any one variation. Application to the determination of the HLB requirements of mixed-oil phases is also discussed. INTRODUCTION The HLB concept (hydrophile-lipophile balance of a nonionic emulsifier) was introduced by Griffin (1). It has since been refined and extended by Griffin, Carter, and their group (2, 3), and summarized by Griffin (4). The practical value of the system to technical people in the cosmetic, detergent, and emulsion fields has been amply demonstrated. This system provides a unifying method which embraces several families of surfactants, and divides the effort required to select the most effective agent to use in a particular project. The HLB of an emulsifier is a number which expresses the ratio be- tween water-soluble groups and oil-soluble groups in the molecule. The higher the HLB number, the more water-directed is the entire molecule. Surfactants of a given chemical type can be arranged in a series, starting with the most oil-directed and advancing to the most water-directed as * Millmaster-Onyx Corp., Onyx Chemical Co. Div., 190 Warren Street, Jersey City, N. J. 07302. 129