320 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 150 '•: 100 -- ._ .-=- 50 SLS10% 1:0.08 1 .0.10 1:0.13 1'0.17 1:0.25 1:0.50 1'100 SLEC-51.6% Baseline • Day 1 '• Day 2 • Day 3 • Day 4 • Day 5 Figure 1D. Laser Doppler flowmetry--Mean baseline and post-patch application values with varying molar ratios of 1.0% SLS:SLEC-5. SLS 1.0% 1 ' 0.08 1 ' 0.10 Baseline ,• Day 1 '0.13 Day 2 1:017 1 '0.25 1 .0.50 1 '1.00 SLEC-51.6% • Day 3 • Day 4 • Day 5 Figure 1E. Skin color reflectancesMean baseline and post-patch application values with varying molar ratios of 1.0% SLS:SLEC-5. significantly different from the Day 2 ratio. Statistical differences were found between the two groups of panelists on Days 3, 4, and 8 (Table V). TRANSEPIDERMAL WATER LOSS MEASUREMENTS In the group of panelists treated with mixtures of SLS and SLEC-5 (Table III), skin response •50% of the SLS value was induced on Day 2 by a mean molar ratio of 1:0.10. The ratio declined steadily and significantly to 1:0.16, 1:0.20, and 1:0.28 on Days 3, 4, and 5, respectively. On Day 8, the mean molar ratio of ! :0.09 was not significantly different from the Day 2 ratio.

ASSESSING REDUCTION OF SLS IRRITATION 321 25 to 2 0.5 o ! SLS 1.0% 1'0.08 1'0.10 1'0.13 1:0.17 1'025 1'050 1'1.00 SLEC-13 2.8% • Baseline • Day 1 [• Day 2 [• Day 3 • Day 4 • Day 5 Figure 2A. Erythema--Mean baseline and post-patch application scores with varying molar ratios of 1.0% SLS:SLEC- 13. SLS 1.0% Baseline • Day 1 ß 008 1:010 1.0.13 1:0.17 1'0.25 1'0.50 1'1.00 SLEC-132.8% ,•-• Day 2 •[• Day 3 • Day 4 • Day 5 Figure 2B. TEWL--Mean baseline and post-patch application values with varying molar ratios of 1.0% SLS:SLEC- 13. With respect to the panelists treated with SLS and SLEC-13 (Table IV), the mean molar ratios of 1:0.10, 1:0.10, 1:0.12, and 1:0.18 induced •50% of the SLS value on Days 2, 3, 4, and 5, respectively. The ratio of 1:0.09 on Day 8 was not significantly different from the Day 2 ratio. Statistical differences were found between the two groups of panelists on Days 3, 4, and 5 (Table V). ELECTRICAL CONDUCTANCE MEASUREMENTS In the group of panelists treated with mixtures of SLS and SLEC-5 (Table III), the mean molar ratio inducing •50% of the SLS value decreased progressively from 1:0.08 on