CHANGES IN STRATUM CORNEUM 119 p ieO-- Surfactant e i70 r t60 c i50 t40 o SLS e n i20 t •o a g 9o e 80 x SLES 7O c 6O h 5O a 4O n 3o 20 g iO • PEG20 e 0 Day]. Day: = Day3 Day4 Day5 Fina! Evaluation time Figure 8. Relative change of redness (treated vs. control--cycle 2) during one week of daily treatments, January-February 1990. Table IX Mean L* Values (S.D.) of Treated Sites in Test Cycle 1 During One Week of Daily Treatments, October-November 19897 Baseline Day 1 Day 2 Day 3 Day 4 Day 5 Final 64.85 64.59 64.74 64.47 61.18 59.82 59.19 SLS (1.44) (1.03) (1.12) (1.84) (2.01) (1.22) (2.03) 63.20 62.92 63.14 62.41 63.15 63.12 63.29 SLES (1.96) (2.13) (1.78) (0.99) (1.58) (1.64) (1.45) 64.06 64.45 63.81 64.03 64.16 64.28 63.64 Tallowate (1.23) (1.75) (1.50) (1.34) (1.58) (1.38) (1.88) Each value is the mean of six subjects. Represents a significant difference at p = 0.05 level from the baseline value within each subgroup. noted at days 4 and 5. With SLES, a minimal scaling condition developed in some of the subjects after two to four days in test cycle 1, but the results were not statistically significant. During test cycle 2, the mean scaling scores showed significant increases at days 4, 5, and 8. No statistically significant changes were noted with respect to erythema or fissuring in either test cycle. No visible changes were detected on any sites patched with either PEG-20 glyceryl monotallowate or water.

120 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table X Mean L* Values (S.D.) of Treated Sites in Test Cycle 2 During One Week of Daily Treatments, January-February 19907 Baseline Day I Day 2 Day 3 Day 4 Day 5 Final 66.85 66.29 65.52 62.40 • 60.32 • 56.52 •'• 57.96 z SLS (1.51) (1.72) (1.90) (2.31) (1.48) (1.77) (1.94) 65.11 65.70 65.04 64.79 64.73 65.49 65.32 SLES (1.50) (0.14) (1.91) (1.44) (1.69) (1.34) (1.31) Tallowate 65.34 65.91 65.91 66.25 65.80 65.86 65.76 (1.33) (0.94) (1.16) (0.94) (1.32) (1.01) (0.93) Each value is the mean of six subjects. Represents a significant difference at p = 0.05 level from the baseline value within each subgroup. Represents a significant difference at p = 0.05 level from the previous day within each subgroup. Figure 9. Relative change of brightness (treated vs. control-•cycle 1) during one week of daily treatments, October-November 1989. IMAGES OF SKIN REPLICAS AND IMAGE ANALYSIS Figures 11, 12, and 13 each show four images of skin replicas taken from the same patched site of a representative subject from each subgroup at pretest, day 3, day 5, and day 8. The progressive changes of the skin surface following repeated exposure to SLS are shown in Figure ! 1. Replicas of SLES and PEG-20 glyceryl monotallowate treatment sites are shown in Figures 12 and 13, respectively, which show only minimal changes.