MILDNESS OF LAUNDRY DETERGENTS DIFFERING IN pH 91 MATERIALS AND METHODS CHEMICALS Commercial laundry detergents All Free Clear® (AFC), All Free Clear Mighty Pacs® (AFCMP), Tide Free and Gentle® (TFG), and Tide Pods Free and Gentle® (TPFG) were purchased at a U.S. retail outlet in the United States in 2017. Tide® and All® are manufac- tured by the Procter & Gamble Company (P&G, Cincinnati, OH) and Sun Products Corp. (Wilton, CT), respectively. Active Wheel® (AW Hindustan Unilever Ltd., Mumbai, India) was purchased in India in 2017. Ivory Bar® soap (IB P&G) was purchased at a U.S. retail outlet in 2017. ReagentPlus® (≥98.5%) grade sodium lauryl sulfate (SLS which is also known as sodium dodecyl sulfate) was manufactured by, and purchased from Sigma Chemical Com- pany (St. Louis, MO). All other chemicals were United States Pharmacopeia (USP) grade. CLINICAL STUDY METHODS Protocols for the two randomized (right–left and site), balanced, double-blind arm studies described in the following paragraphs were reviewed and approved by independent insti- tutional review boards. The studies were supervised by an independent dermatologist, and were monitored by P&G personnel to ensure that they were conducted in compliance with the protocol and with Good Clinical Practices as specifi ed under 21 Code of Federal Regulations (CFR) 321.66. Before participating in the studies, each subject signed a written informed consent that contained all the basic elements outlined in 21 CFR 50.25. REPEAT INSULT FOREARM TEST (RIFT) This mini-immersion, repeat insult method is a 1-d study modeling the skin effects of exposure to detergents during hand-laundering. It was conducted in Beijing, China, in August of 2017. For the study, 80 female subjects (ages 20–45 years) in general good health with self-described sensitive skin were recruited, and all of them completed the study without adverse events. The subjects were instructed to not use lotions or cosmetic products on their forearms for 3 d before the start of the study and for the duration of the test. During that time, they were provided with commercial IB soap for washing and bathing. They were also instructed not to expose their forearms to soap or water in the 3 h before the visit on the day of the study. On the day of the study, subjects were acclimated for at least 15 min under controlled temperature and humidity conditions (21° ± 2°C and 45–55% relative humidity) im- mediately before the start of the study and remained in that environment for the duration of the study (approximately 5 h). After the 15 min of acclimation, visual grading was carried out by two trained graders using grading scales: erythema (0–4 scale) and skin dryness (0–5 scale). Then, noninvasive instrumental measurements were carried out in the following order: corneometry with a Corneometer® CM 825 (Courage and Khazaka Electronic, Cologne, Germany), transepidermal water loss (TEWL) with a Delfi n VapoMeter (Kuopio, Finland), and pH with a Hanna Instruments HI99181 skin pH meter (Woonsocket, RI). These measurements were repeated 40 min after each of the subsequent four expo- sures to test treatments, which was just before the subsequent treatment.

JOURNAL OF COSMETIC SCIENCE 92 In the study, the corners of three 3.5 × 3.5-cm2 sites on each inner (volar) forearm were marked (using a black permanent marker) for a total of six treatment sites. To simulate real-world conditions, all the treatments (except the water negative control) contained minerals (4:1 ratio of CaCl2:MgCl2) to create water hardness. The typical units for hard- ness are grains per gallon (gpg): 1 gpg = 1 part in 58,000 parts of water = 17.1 mg/kg (also reported as parts per million or ppm) of minerals. The six treatments were distilled deionized water (negative control) containing 0 gpg water hardness, 0.5% SLS containing 16 gpg water hardness (positive control), 1% SLS containing 16 gpg water hardness (positive control), 4,200 mg/kg solution of AW containing 16 gpg water hardness (posi- tive control), 4,200 mg/kg solution of TFG containing 7 gpg water hardness, and 4,200 mg/kg solution of AFC containing 7 gpg water hardness. SLS is a demonstrated irritant for volar forearm skin (20), and AW has been used as a positive control in other studies with Procter and Gamble (P&G manufacturer data on fi le). Water containing 16 gpg is considered hard water, which is harsher to the skin (21), thus making the SLS and AW solutions high harshness controls. Seven grains per gallon is the average water hardness for tap water in the United States, and the investigators wanted to mimic hand-wash conditions in the United States. Solutions of 4,200 mg/kg TFG and AFC (equivalent to one manufacturer-recommended dose of liquid detergent in 5 gallons of water) were cho- sen as reasonable doses of detergent for handwashing of laundry. TPFG and AFCMP were not included in this study as laundry detergent pacs are less likely to be used than liquid detergents in hand-laundering, prewashing, or pretreating of garments. The treatment solutions were prepared at room temperature (approximately 22°C) on the morning of the study. Before application to the skin, the solutions were warmed to 35° ± 2°C in a water bath and mixed on a magnetic stirrer to ensure homogeneity. Each subject had a total of four exposures to each of the test treatments for 15 min on the marked sites on the inner forearm, with a 1-h interval between the start of exposures. For exposure, subjects placed their forearms fl at on a clean draped surface with the inner forearm facing upward. Glass exposure cups (1.9-cm-tall × 2.1-cm-inside-diameter polished glass cylin- ders) were held against the forearms with Velcro® bands (Velcro China Fastening Systems Comp. Ltd., Zhangjiagang, Jiangsu Province, China). Three milliliters of treatment solu- tion was introduced into the exposure cup for 15 min of exposure, after which the treat- ment solution was removed by pipette, the skin was rinsed with running water (22° ± 2°C) for 15 s (with gentle rubbing with gloved fi ngers to remove residual test material for the last 5 s of the rinse), and the skin was patted dry with a commercial paper towel. Rinse water for each test site had the same water hardness (gpg) as that used for the test solutions. For the subsequent exposure, exposure cups were repositioned on the same forearm sites in the skin indentations that remained from the previous exposure. Noninvasive instrumental measurements (corneometry, TEWL, and pH) and visual grad- ing (redness and dryness) were carried out at baseline and at 40 min after each exposure to test treatments, and before the subsequent treatment. Erythema (0–4) and skin dryness (0–5) scores were measured separately by two trained graders, and those scores were aver- aged. The order of measurements was as follows: visual grading, corneometer, TEWL, followed by skin surface pH testing. For statistical analysis of the data, the skin grade values for erythema and dryness from both graders were averaged for further analysis. For variables that have a continuous distribution, the posttreatment evaluations (each exposure after baseline) were analyzed using mixed-