JOURNAL OF COSMETIC SCIENCE 62 SKIN SURFACE LIPID MIMETIC FORMULATION Refi ned jojoba oil, macadamia oil, ethyl macadamiate (Floratech), squalene (Ekiz, Izmir, Turkey), and phytosterols (ADM Nutrition, Decatur, IL) were used to formulate the mi- metic. The jojoba and macadamia oil underwent a transesterifi cation process under typical conditions in order to distribute the palmitoleic acid among both the wax-ester and triglyc- eride portions of the material. Ethyl macadamiate and phytosterols were transesterifi ed in a similar process to create a phytosteryl ester of macadamia FAs thereby incorporating palmi- toleic acid in the phytosteryl ester portion of the mimetic. The transesterifi ed products of wax esters, triglycerides, and phytosteryl esters along with squalene and phytosterols were mixed in specifi c quantities resembling SSLs in the fi nal formulation. EFFICACY ANALYSIS OF TOPICAL APPLICATION OF SSL MIMETIC Four effi cacy studies were conducted in Chandler. Independent review board approval and a written informed consent from each subject were obtained before any protocol-related procedures were undertaken. All study participants were healthy females. Upon arriving at the testing facility, subjects acclimated for 30 min in a controlled environment (20°– 22°C, 50% RH). All studies were carried out in a double-blind, vehicle-controlled, randomized manner according to the testing matrix (see Table I). The vehicle contained the following: water (q.s.), methylisothiazolinone and caprylyl glycol (0.9%), ammonium acryloyldimethyltaurate/VP copolymer (0.6%), sorbitan and sucrose cocoate (0.5%), hy- droxyethylcellulose (0.3%), and disodium ethylenediaminetetraacetic acid (0.1%). The SSL mimetic was compared to olive oil (OO) and caprylic/capric triglyceride oil (CCT) because these also contain skin-lipid-like components. RESULTS SKIN SURFACE LIPID COMPOSITION AND COMPARISON The initial portion of this study was to evaluate variation in the SSL composition within a population where age and sex were controlled. The sensitivity of GC-MS analysis allows Table I Effi cacy Testing Matrix Function Washout (days) Anatomical location n Sex Instrumenta Insult/condition Short-term barrier recovery 2 Volar forearms 14 M/F Tewameter TM 300 Acetone exposure Short-term hydration 2 Lower legs 12 F Corneometer® CM 825 Dry skin Long-term skin hydration and barrier function 3 Lower legs 18 F Corneometer CM 825/Tewameter TM 300 Dry skin Viscoelasticity and hydration 2 Forearms 13 M/F MPA Cutometer/ Corneometer CM 825 Aged/sun-damaged skin (60–80 years of age) aAll instruments are products of Courage + Khazaka (Köln, Germany).

BOTANICALLY DERIVED SKIN SURFACE LIPID MIMETIC 63 for differentiation of not only primary SSLs but also differentiation and quantifi cation of constituent FAs. The data in Table II demonstrate the mean percent composition of each SSL component, as well as the skin surface composition of the SSL mimetic. The most abundant component of SSLs was the glycerides. Relatively speaking, of the six SSL com- ponents evaluated, FFAs and cholesterol varied the most between subjects however, when glycerides and FFAs were combined, the variation of the combination decreased greatly compared to the variation of either individual component. For the purpose of correlation analysis, glycerides and FFA were combined due to the variation in the degree of hydrolysis of triglycerides by bacteria (20). Triglycerides are broken down into diglycerides, monoglycerides, and FFA therefore, the variability be- tween these components is highly dependent on the microfl ora of the individual (16). Correlations between the fi ve components were calculated yielding statistically ( p 0.05) or directionally (p 0.10) signifi cant correlations between all components with the ex- ception of the following: squalene and wax esters, and cholesteryl esters with squalene or cholesterol, indicating that the cholesteryl ester and squalene compositions may vary in- dependently of other components. SSL MIMETIC EFFICACY (3%) WHEN APPLIED TOPICALLY In the fi rst study, the SSL mimetic increased barrier recovery statistically signifi cantly ( p 0.001) better than 3% OO, 3% CCT, and the vehicle 60 min posttest article appli- cation. These increases were amplifi ed with the inclusion of ceramide 2 (C2), which provided the greatest amplifi cation compared to the other skin-lipid-like emollients (Figure 1). In the second study, the test article containing the SSL mimetic produced statistically signifi cantly ( p 0.05) higher percent changes in skin hydration than all other test ar- ticles. The addition of C2 seemed to act synergistically when combined with the SSL mimetic (Figure 2). In the third study, the SSL mimetic produced statistically signifi cantly (p 0.05) higher percent changes in skin hydration than 3% petrolatum after 1 and 2 weeks of test article use, and following a 1-week regression. Additionally, the SSL mimetic produced statistically signifi cantly ( p 0.05) larger decreases in transepidermal water loss (TEWL an indica- tion of improvement in skin barrier function) after 1 and 2 weeks, and following a 1-week regression (Figure 3). Also, 1 h after application, both products statistically equivalently Table II Mean Percent Composition for SSLs and SSL Mimetic SSL component Mean percent composition ± standard deviation Mean percent composition of SSL mimetic Squalene 15.6 ± 4.8 14.10 Wax esters 15.2 ± 3.2 18.40 Cholesterol (phytosterol) 0.6 ± 0.4 0.40 Cholesteryl esters (steryl esters) 2.1 ± 0.6 1.90 Glycerides 50.3 ± 12.5 FFAs 16.2 ± 10.2 Glycerides and FFAs 66.5 ± 6.2 65.20