EXOGENOUS DISULFIDE IN HAIR REDUCTION 107 REFERENCES (1) J. W. Haefele, U.S. Pat. 2,719,813 (1955). (2) J. W. Haefele, U.S. Pat. 2,719,814 (1955). (3) J. H. Sanders, U.S. Pat. 2,719,815 (1955). (4) E. J. Klemm, W. W. Edman, F. E. Erskine, and E.G. McDonough, U.S. Pat. 4,273,143 (1981). (5) C. R. Robbins, Chemical and Physical Behavior of Human Hair (Van Nostrand Reinhold Company, 1979), pp. 43-44. (6) D. Sanford and F. Humoiler, Analytical Chemistry, Vol. 19, pp. 404-406 (1947).

J. Soc. Cosmet. Chem., 38, 109-124 (March/April 1987) Infrared characterization of human sweat glands inhibited with aluminum chlorohydrate JOHN STRASSBURGER and DON W. COBLE, Gillette Research Institute, 1413 Research Boulevard, Rockville, MD 20850. Received October 3 O, 1986. Synopsis Sweat glands from human forearm were inhibited by application of aluminum chlorohydrate (ACH). Poral occlusions in the sweat glands were demonstrated, microdissected, and characterized by Fourier transform infrared spectroscopy. The occluded areas were composed of an aluminum-stratum corneum complex. In vitro treatment of stratum corneum was used to show ACH coordination to carboxylate groups. Ligand binding to nitrogen-containing groups was also indicated. The implication of the aluminum-keratin inter- action in the mechanism of antiperspirant action is discussed and a vital role is suggested. INTRODUCTION Of the various proposed mechanisms for aluminum salt-induced anhidrosis, one general hypothesis is the most widely accepted. Aluminum and other metallic salts that have antiperspirant activity are believed to form an obstruction or plug that blocks the flow of sweat within the eccrine sweat gland. The initial proponents of this so-called plug theory were Shelley and Horvath (1,2), who described hyper- and parakeratotic plugs within sweat ducts after application of aluminum (III) chloride. Later Shelley and Hurley (3) stated that "aluminum combines with the intraductal keratin fibrils, pro- ducing a functional closure, a supercontraction not apparent histologically. The fixed keratin remains as an obstructive block to the free egress of sweat . . ." Reller and Luedders (4) proposed that metal salts formed polymeric metal-hydroxide gels by the slow neutralization of acidic metallic salts in the sweat gland duct. This postulate was derived from their ability to correlate antiperspirant activity of a number of metallic salts with the plugging of millipore filters by neutralization with ammonia vapor. Holzle and Kligman (5) speculated that metal ions formed precipitating complexes with mucopolysaccharides, which damaged luminal epithelial cells and generated an obstructive conglomerate within the acrosyringium. While first rejecting the horny plug theory, they then implicated viable luminal cells as part of the obstruction, appar- ently as a secondary effect. They further stated that these cells subsequently died, sloughed into the lumen, and became part of the obstruction. More recently, Quatrale et al. (6), showed that eccrine sweat units treated with aluminum chlorohydrate (ACH) produced a ductal lumen completely filled with an electron-opaque amorphous mate- 109