154 JOURNAL OF COSMETIC SCIENCE of moisture and the semi-occluded nature of a diaper. Transepidermal water loss (TEWL) readings for baby's skin in the diaper area are markedly higher than TEWL readings for undiapered skin. As a result, diapered skin demonstrates a background level of irritation that can mask slight differences in the effects produced by different products. Clinical studies, where a panel of consumers actually use the products under evaluation for an extended period of time, have been used to study mildness and other skin effects. However, such studies for baby wipe products are extremely costly and time-consuming. Further, there are a number of factors that can confound the results, such as the ap- pearance of diaper rash, heat rash, yeast infections, bacterial infections and other skin diseases, or variations in the use habits and practices of parents. A practical, cost-effective test method was needed that would evaluate the relative mildness of various product formulations on skin that was in a state of hydration. Other investigators have been successful using the FCAT to determine the relative mildness of a variety of personal cleansing products (5). Therefore, we chose to develop a modified FCAT specifically for evaluating baby wipes. The developmental program consisted of two phases run concurrently. The patch system development phase involved four small-scale tests designed to devise a practical and effective system for producing hydrated skin in the test site area. The two main variables examined were: (a) the use of synthetic urine versus water for hydration, and (b) the patch system used to achieve a semi-occluded environment. The FCAT modification phase involved three tests using baby wipe products. The main variables examined in this phase were: (a) the specific duration of test product application, (b) the need for a conditioning or pretreatment period, and (c) the minimum overall test duration and number of subjects required to achieve significant differences between products. MATERIALS AND METHODS PATCH DEVELOPMENT PHASE Materials. Modified diaper patches were 4" x 6" rectangles cut from the core area of commercially available disposable diapers (Pampers Baby Dry©). These were saturated with 60 ml of fluid and applied to test sites by wrapping the diaper patch with Kerlix © mesh and securing it with 3M Blenderin © tape. Alternatively, patches consisted of Johnson 8: Johnson Band-Aid © Brand large adhesive pads (27/8" x 4") saturated with 5 ml of fluid. In some experiments, the adsorbent pad of the bandage was supplemented with a 3" x 3" sterile gauze pad folded once, and/or the bandage adhesive was reinforced with Blenderin © tape. When the gauze pad was used together with the bandage, 9-10 ml of fluid was used to saturate the patch. Synthetic urine consisted of 0.2% KCI, 0.2% Na2804, 0.085% (NH4)H2PO4, 0.05% MgCI 2 ß 6H20, 0.025% CaCI 2 2H20 , and 0.015% (NH4)2HPO4 in deionized water. FCAT MODIFICATION PHASE Materials. Four different currently marketed baby wipes were used in these experiments. These are referred to as products A, B, C, and D. All four of these products have been safely marketed for many years. Products A and B were Procter & Gamble brands. Internal, unpublished data available on these products indicate they are "very mild" in

MODIFIED FCAT 155 a 21-day cumulative irritation test (6). In a four-day patch test (internal company protocol using semi-occluded patches on four consecutive days), these products are comparable to the negative irritant controls (water and isotonic saline). The products are non-irritating and are negative for sensitization and in human repeat insult patch tests (7). Forearm washing protocol. In tests involving comparisons of baby wipe products, baby wipe application consisted of repeated washing cycles of the defined test sites with the test products. Washing sessions were 1 • hours apart, and were conducted four times each day, with the exception of the final day of the test, when one or two washing sessions were conducted. For each washing cycle, a baby wipe was folded twice, and wiped in a back and forth motion with light pressure on the test site for either 15 or 30 seconds. In some studies, the baby wipe was refolded to expose an unused portion, and the back and forth wiping was repeated. In some studies, the duration of the washing procedure for the last washing session of each day was doubled by using a second baby wipe and repeating the two-step washing procedure. The technicians conducting the washing procedure were instructed to take care to apply equal pressure to all test sites. A study of specific differences in the washing protocol are given below in the Results section. BOTH PHASES Subjects. For each study, the protocol was approved by the test facility's Institutional Review Board. Participants in all studies were healthy adult volunteers, ages ! 8-65, who had signed an informed consent form. Subjects were excluded from participation if: (a) they had allergies to soaps or fragrances, (b) they were taking anti-inflammatory corti- costeriods or other medications that may interfere with test results, (c) they had active dermatitis, (d) they were pregnant or lactating, or (e) they had sunburn, acne, scar tissue, or other skin abnormality at the test site. In addition, for experiments during the FCAT modification phase, subjects were excluded if they had participated in a forearm patch test within four weeks prior to the study. Initial studies used both male and female subjects. However, the relatively high amount of body hair on the forearms of the male subjects made visual scoring for erythema and dryness difficult. Therefore, the final two studies used female panelists only. For each panelist, the forearms were divided into upper and lower test sites. These sites were at least 2 cm apart, and 2 cm from either the elbow or the wrist. Test patch systems or products were assigned to test sites using a randomization schedule. Panelists in each study were given the same brand of bar soap to use for personal cleansing and instructed not to use lotions, cremes, or moisturizers on the test sites, nor to wash the test sites during bathing throughout the duration of the test. In those experiments where modi- fied diaper patches were used, subjects were instructed to put a plastic bag on the arm to cover the modified diaper patch while bathing or showering. Evaluation of skin condition. In these experiments, transepidermal water loss (TEWL) was measured using a ServoMed Evaporimeter EP ! © employing standardized procedures (8). This instrument concurrently measures evaporation rate (range 0-300 g/m2hr), relative air humidity, and water vapor partial pressure. Readings were taken in triplicate. All measurements were taken after the subjects had spent a 30-minute acclimation period in the test facility's controlled temperature and humidity room. Specific room settings