EFFECT OF DIMETHYL SULFOXIDE 30 KEY • BSA (0.1M KCI) 20 C) BSA . (0.1M KCI ) 2-• • - i I I 2.0 3.0 4.0 5.0 pH Figure 1. Effect of DMSO on viscosity of BSA (25 ø • 0.0bøC) 167 eter (each division = 0.01 mm). The same procedure was carried out on pieces of the hair which had been submerged in 100% DMSO for approximately one week. RESULTS Initial experiments were designed to ascertain whether dioxane which has been demonstrated to cause an expansion or swelling of soluble proteins (8) might be capable of altering percutaneous permeability. Dioxane was therefore tested in the picrate ion-guinea pig skin diffusion system (1). As the results in Table I indicate, a marked enhancement of the percutaneous absorption of the picrate ion was observed. The skin membranes, although swollen, did not appear hard and turgid as was the ,case with DMSO.

168 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I Effect of Dioxane on Percutaneous Absorption of Pierate Ion" Solvent Initial Concentration Absolute Rate Constant Enhancement of Pierate (M) (cm hr-1) Due to Solvent Buffer control • 3.38 X 10 -2 1.23 X 10 -4 ... 80%Dioxane b 6.70 X 10 -2 17.6 X 10 -4 14.3 Buffer control c 5,08 X 10 -2 1.22 X 10 -4 ... 80% Dioxane c 4.44 X 10 -2 21.3 X 10 -4 17.5 Buffer control a 5.02 X 10 -2 1.45 X 10 -4 ... 70% Dioxane a 5,84 X 10 -2 16.9 X 10 -4 11.6 • Male guinea pigs were sacrificed with lethal injections of MgSO4. The abdominal skins were immediately shaved, excised, and frozen. The skins were kept frozen until use. b The length of time between procurement and utilization of the skin, 20 hours. • The length of time between procurement and utilization of the skin, 24 hours. a The length of time between procurement and utilization of the skin, 18 hours. Table II Effect of 30% DMSO upon the Reduced Viscosity of Beta Lactoglobulin (at 25 ø q- 0.05øC) pH Reduced Viscosity (ee/g) A. Beta lactoglobulin in 0.1M KC1 2.95 3.80 2.65 3.51 2.42 4.31 2.00 4.56 B. Beta lactoglobulin in 30% DMSO (0.12M KC1) 3.10 6.77 2.72 7.05 2.20 6.78 Table III Effect of DMSO Concentration on the Equilibrium Liquid Retention of Hair DMSO Concentration (% v/v) • Liquid Retention (Average of four results and standard deviation) 0 33.02 q- 0.51 20 32.52 q- o. 49 40 34.45 4- o. 33 60 37.70 4- o. 26 80 46.12 q- 0.88 90 59.08 (average of two results) 100 68.14 q- 1.51 (average and std. der. of 12 results)