176 JOURNAL OF COSMETIC SCIENCE Controlled usage tests: Exposures in these tests can mimic the actual use or they can be exaggerated to assess the potential impact of misuse/abuse. These tests typically involve rigorous controls such as supervised application and use thus reducing variability and assuring compliance. They can also differentiate between products that are inherently very mild or aid in evaluating perceived skin effects ( e.g. pain, burning, itching or stinging) that are not always evident from the results of patch testing. Several test methods will be discussed including immersion tests, the Forearm Controlled Application Test (FCAT), the Leg Controlled Application Test (LCAT), the Antecubital Fossae Test, and the Behind the Knee (BTK) Test. Consumer home use tests: Home usage tests reveal the irritation potential of the test materials during actual consumer use. It is important in these designs to control as many factors as possible so that any irritation seen, or not seen, can be associated with the test material used. These tests are less robust than the controlled use tests and generally require larger base sizes to compensate for the increased variability. Study Design and Statistical Considerations Statistical rigor begins at the design stage of any study. The study design process consists of convening a study design team, defining the study objective, determining the data to collect, choosing the sample size and the appropriate statistical analysis. It is important to enlist all factions that have a vested interest in the research as well as others that may be able to assist. This study design team needs to determine the study objective. Once the objective has been defined, study parameters can be developed. Sample sizes for irritation studies can be derived using statistical calculations as well as from standard requirements from regulatory agencies. Basic test designs for irritation studies are similar, clear objectives are needed, the objective will drive the design and the design will drive the analysis. Parametric as well as non-parametric approaches are used to appropriately evaluate data. Investigator judgment may be just as important as statistical analysis and it is critical to understand the differences between statistical significance and clinical relevance. Inter-individual variability tends to dominate other sources of variability such as seasonality and ethnicity. Consequently, when designing irritation studies to discriminate between ingredients/products, inclusion of positive and negative controls can aid in calibrating the subject panel. New Endpoint Measures Visual scoring has been the cornerstone of skin irritation testing. Trained skin graders can accurately and reproducibly score test sites for erythema and dryness. Physiologic changes in blood flow, moisture content, pH, etc. occur early in the irritation process before any visible reactions. These early changes may be critical to distinguishing subtle effects and differentiating between products. Techniques such as TEWL, polarized light, electrical impedance, 2-D & 3-D ultrasound, laser Doppler velocimetry, immunoassay for inflammatory biomarkers, and quantitative measures of transient sensory responses have brought new technical insight into the irritation process and detection of product differences. These non- invasive techniques can improve the quality and relevance of data since they provide objective and quantitative measures. Summary All substances possess some potential irritancy which must be fully evaluated to ensure that marketed products are not unacceptably irritating. With the wide range of ingredients and formulations to be evaluated, adequate thought and preparation must go into the evaluation strategy. In patch testing, prolonged contact under occlusion is expected to reveal whether a substance has demonstrable irritancy potential. However, its potential under use conditions may not be evident. By spreading the evaluation over a spectrum of exposure conditions, a truer evaluation of irritation potential is obtained than by merely taking a single reading at an arbitrary point. Rigorous product assessment is critical in the product development process to assure safety and consumer acceptance.

2007 ANNUAL SCIENTIFIC MEETING 177 ETHNIC SKIN: UNIQUE PROPERTIES, CHALLENGES AND SOLUTIONS Victoria Holloway Barbosa, MD Dermal Insights, Inc. The ability to address the skin care needs of people of different ethnicities has never been more important, as both the United States becomes more diverse and as international companies make products that serve people from more countries around the world. In order to successfully meet these needs, the cosmetic chemist must first understand them. This includes having knowledge of the similarities and the scientifically proven differences in the skin of people of different origins. It also requires insight into the different desires and challenges of people from different cultures, both within the US and around the world. Finally, one must be familiar with the current product offerings in order to know the unmet needs. This presentation will review the published literature and recent reports on the differences in skin across ethnicities. Structural and functional differences will be discussed. The differences that are of cosmetic relevance will be highlighted. In addition to covering normal skin, common skin conditions and diseases of significance to people of color will be discussed. Problems with pigmentation provide one of the greatest challenges for people with skin of color. Problems including normal variation in facial pigmentation (especially around the eyes and in the beard region), conditions such as postinflammatory hyper- and hypopigmentation, and diseases such as melasma and vitiligo will be described. A review of the effects of acne in pigmented skin, dry skin, eczema will also be provided, as will a review of the skin challenges associated with facial hair growth. Allergic reactions and sensitive skin will also be discussed. For the conditions, a description of the underlying cause will be given and clinical examples will be shown. There are many skin care products currently available that address some of the skin care needs of consumers from diverse ethnic backgrounds. However, there are still many unmet needs which translate into opportunities for the cosmetic chemist. Some of the products are developed for and/or marketed specifically to people of color. Other products are mainstream products but are particularly effective or appealing to people of color. This presentation will review existing brands, products and active ingredients. Finally, a needs analysis will be given based on what we know about the skin and what is currently offered. These need-gaps will be presented as challenges to the cosmetic chemist. At the end of the presentation, the chemist should have a good understanding of ethnic skin, its specific properties, and conditions and diseases that are relevant to its skin care needs. He or she will be aware of products that are currently available, and opportunities for improvements in current offerings.