SURFACTANT PENETRATION INTO HUMAN SKIN AND RESULTING SKIN DRYNESS 35 with Fitzpatrick skin types I–IV were recruited. Subjects who had recently (within 3 weeks of enrollment) participated in another forearm study at this or any other facility were excluded from participation. In addition, subjects who were allergic to the ingredi- ents of personal care products or to tapes/adhesives, who had active eczema or psoriasis on any portion of the body, who had a history of cancer, with recent use of topical medica- tions on the forearms, with chronic use of any medication that could inhibit the appear- ance of irritation, who had a history of diabetes, with use of moisturizers on the forearms 24 h before baseline measurements, with demonstration of abrasions or scarring of the forearms, with any immunologic or infectious disease, who were pregnant or lactating, who had insuffi cient forearm length to accommodate the number and size of test sites, and/or who were an employee of the sponsor or testing site were excluded from participat- ing in this study. Because of the cosmetic nature of this study, the use of non-regulated test articles and/or monograph ingredients, and the low risk to study subjects (normal expectation), an institutional review board (IRB) was not used for review/approval of this clinical study. This decision conformed to the sponsor’s standard operating procedure on IRB review. The FCAT was a randomized, double-blinded (subject and grader/instrument operator), round-robin design. Fifteen test formulations were randomized to six sites per subject (three on each forearm), yielding N = 28/formulation. After reviewing study deviations, subject medications, adverse events, and subject/test site drops, 22–24 measurements were completed for each formulation. Tape strip extractions were only completed on a subset of seven of the total 15 formulations as it was not possible to analyze tape strip samples from all 15 formulations in regard to time and cost. The subset of formulations chosen (listed in Table I) comprises mild and harsher treatments, including both internal controls and a sampling of the competitive market at the time of the study. Cup scrub extractions were completed on all study participants, but the results shown here are of a subset matching the tape stripped population. Thus, because of the incomplete block design and our interest in certain formulations over others, sample sizes vary across mea- surements completed in the FCAT. The method was adapted from Ertel et al. (9) with deviations highlighted below. Each study participant had three application areas (5 cm × 5 cm) marked off on the volar surface of each forearm with a laboratory marking pen, totaling six test sites. A clinical assistant wetted the participant’s volar forearm with warm tap water (35°C) and then applied the test formulation, beginning with the site nearest the elbow, by dispensing the appropriate amount of test formulation into the center of the marked area. Test formulations varied Table I Compositions and Codes of the Test Formulations Examined in this Study Code Total composition (% w/v) Surfactants quantifi ed using tape strips and cup scrubs A SLE1S (12), CAPB (2), CMEA (1) SLE1S, CAPB B SLE1S (9), CAPB (5), CMEA (1) SLE1S, CAPB C SLE1S (9), SCG (5), CMEA (1) SLE1S, SCG D SLE1S (11), SLE3S (1.5), NaLAA (8.15) SLE1S, NaLAA E SLE1S (11), SLE3S (1.5), NaLAA (8.15), PVA (8) SLE1S, NaLAA F SLE1S (12), CAPB (2), CMEA (1), CPVA (2) SLE1S, CAPB G EcoSense (12), CAPB (2), CMEA (1) EcoSense, CAPB

JOURNAL OF COSMETIC SCIENCE 36 in concentration, but each formulation was applied such that 37.5 mg of total surfactant was delivered to each area. The assistant then used a gloved hand to lather by a circular motion within the test site for 10 s. The lather remained on each site for 90 s, after which the site was rinsed with warm water for 15 s. The formulation application and rinse proce- dure was repeated on the remaining fi ve test sites of one subject, with each test site receiving a different test formulation according to the study randomization. After all test sites were rinsed, the clinical assistant patted the subject’s arm dry. This procedure was immedi- ately repeated on the same subject. Thus, each wash visit comprised two washes per test site. Wash visits occurred twice a day for the fi rst 4 d and once on the fi nal day for a total of 18 applications. Wash visits were spaced by a minimum of 3 h. Each test site was divided into four quadrants to accommodate multiple evaluations. Although the entire test site received product application, a designated quadrant within the test site underwent specifi c evaluations. Evaluations in the FCAT were conducted twice, once at baseline before formulation application and again 3 h after the fi nal wash. The order of evaluations was as follows: subject acclimation in a temperature and humid- ity controlled environment for 30 min, visual dryness assessed by an expert grader, instru- mental measurement of skin hydration conducted using a Corneometer® CM 825 (Courage + Khazaka electronic GmbH, Cologne, Germany) operated with a multi- pronged probe (model MT-8C Measurement Technologies, Inc., Cincinnati, OH), cup scrub sample collection, and tape strip sample collection. At the baseline visit, the full test site was evaluated for visual dryness, the upper left quadrant underwent tape strip sample collection, the upper right quadrant underwent cup scrub sample collection, and the lower left quadrant underwent instrumental evaluation. Three hours after the fi nal wash, the entire test site was evaluated for visual dryness, the lower left quadrant under- went instrumental evaluation followed by tape strip sample collection, and the lower right quadrant underwent cup scrub sample collection. Each quadrant was only sampled with tape strips/cup scrubs one time throughout the study so that the test site was not compromised before each sample collection. TAPE STRIP AND CUP SCRUB EXTRACTIONS Preliminary work showed that 85–90% (results not shown) of the applied surfactant could be accounted for using fi ve sequential tape strips. Thus, we chose to collect fi ve tape strips in this study. Each D-squame tape (22 mm in diameter Cuderm Corp., Dallas, TX) was pressed on the skin with a constant pressure for 5 s using a D-500 D-squame pressure instrument (CuDerm Corp.). The tape was gently peeled away from the skin with blunt- tipped forceps and another tape was placed in the same location. This process was re- peated with approximately 1 min between tape placements until fi ve tapes were collected. Individual tapes were placed in vials and extracted using 2 mL of a 50/50 v/v mixture of water and methanol. Cup scrub samples were collected by placing a sterile glass cylinder (2 cm diameter) on the participant’s forearm, pipetting 1 mL of a 50/50 mixture of 100 proof ethanol and high performance liquid chromatography (HPLC) grade water into the cylinder, and scrubbing with moderate pressure for 30 s using a sterile glass rod. The ethanol/water mixture was then collected, and this procedure was repeated with another 1 mL of ethanol/ water on the same sample area. The ethanol/water samples were pooled.