MODIFIED FCAT 165 B in Table IV), hydrated skin showed higher scores for all four endpoints when treated in the same manner as normal skin. The experiment summarized in Table III confirms that differences in skin effects are more difficult to detect on hydrated skin. In this experiment five days' duration, we were once again able to detect significant differences in all four endpoints on the normal skin sites. However, on the hydrated skin sites, only the TEWL measurements were signifi- cantly different. The other three endpoints were directionally different, but did not reach significance. By increasing the overall duration of the test to 14 days, as in the experiment summa- rized in Table IV, we were able to achieve significant differences in all four endpoints on the hydrated skin sites. These differences were detected in spite of the fact that the duration of each product application was reduced to better reflect the actual consumer habits and practices of product use. Eliminating the pretreatment period did not appear to compromise the ability to hy- drate the skin sites, as demonstrated by comparing the normal to hydrated value for each product in the 14-day study presented in Table IV, where no pretreatment was used. For all four endpoints, the hydrated skin showed an increase in irritation. A final step in development of this method was to determine the optimum test duration and number of panelists required to achieve significant results. It was possible that a test of 14 days using 80 subjects, such as the one presented in Table IV, was more than absolutely necessary. Statistical analyses of the intermediate points from the experiment presented in Table V indicated that the duration of the test could be reduced to nine days and still produce significant differences between these two products for all endpoints. Subsequent studies have indicated that a test of seven days' duration involving approximately 60 subjects provides consistently reliable results. Table V Summary of Statistical Differences Between Products B and C At Different Time Points in the 14-Day Modified FCAT Day 5 Day 7 Day 8 Day 9 Day 14 Normal skin Erythema Yes • Yes Yes Yes Yes Dryness No Yes Yes Yes Yes Redness Yes -- -- Yes TEWL Yes -- -- -- Yes Hydrated skin Erythema Yes Yes Yes Yes Yes Dryness Yes No No Yes Yes Redness Yes -- -- -- Yes TEWL Yes -- -- -- Yes This is a summary of significant differences at the interim scoring time points for the 14-day study presented in Table IV. Statistical significance for erythema, dryness, and TEWL readings was determined using a Wilcoxon's signed rank test. Statistical significance for chromameter readings was determined using a two-sided paired t-test. • "Yes" indicates a significant difference between Products B and C (p 0.05). "No" indicates no significant difference.

166 JOURNAL OF COSMETIC SCIENCE Interestingly, a shorter duration test, such as the five-day test presented in Table III, may be adequate to provide a quick indication of mildness differences to aid in decisions during product formulation. Although the five-day test did not yield significant dif- ferences for all endpoints, the results demonstrated directional differences. Most of these experiments used both visual and instrumental scoring methods. This provided an opportunity to compare the ability to detect differences when visual scoring was used versus instrumental scoring. In all cases, visual scoring was qualitatively similar to instrumental scoring, indicating that instrumental scoring may not be necessary to provide an indication of the relative mildness differences between products. This would be particularly useful for quick screening studies, where a complete understanding of mildness and irritating effects is not necessary. CONCLUSIONS ß A modified FCAT has been developed that can consistently detect differences in mildness for baby wipe products under hydrated skin conditions such as those found in the diaper area. The test should be of nine days' duration, and use 60-80 female panelists. Washing cycles in the modified FCAT should be conducted four times daily for six to eight consecutive days, and twice on the final day. The washing cycles should be of 15-second duration except for the final washing cycle on each day, which should be 40 seconds. Hydration can be achieved with nightly patches consisting of the J&J bandage with gauze, reinforcing tape, and 10 ml of distilled water. No conditioning or pretreatment period is necessary. Four endpoints should be evaluated: TEWL, redness by chromameter, and erytherna and dryness by visual scoring on seven-point scales. ß This method has applicability for wipes intended for other uses where mildness and irritation are critical considerations, such as wipes intended for cosmetic removal. ß Subjective measurements provide adequate endpoints in the absence of instrumental measurements. Significant differences among visual scores were very consistent with those observed with the instrumental scores. ß An abbreviated test design of five days' duration using visual scoring alone would be a cost-effective approach toward providing an indication of mildness differences to aid in formulation decisions. This abbreviated test can be followed by the more extensive study design given above for a complete understanding of mildness differences and for product claim support. ACKNOWLEDGMENTS The author is grateful to Ms. Sandy Meyer and Ms. Debbie Gilpin for their excellent technical support, to Sue Baldwin, PhD, for her scientific input into this program, to Celeste Kuta, PhD, for her technical input and review of the manuscript, and to Terresa L. Nusair, PhD, of Risk Assessment and Toxicology Services, Inc. (Cincinnati, Ohio) for the preparation of this manuscript. REFERENCES (1) D.J. Kooyman and F. H. Snyder, Tests for mildness of soap, Arch. Dermato/., 46, 846-855 (1942).