Tier-based skin irritation testing of hair cleansing conditioners and their constituents.

The U.S. Food and Drug Administration (FDA) does not require specific testing to demonstrate the safety of personal care and cosmetic products or their ingredients. Recently, there have been reports of skin irritation associated with the use of commercially available cleansing conditioners. The goal of this study was to implement a tier-based safety assessment approach to evaluate the skin irritation potential of six commercially available cleansing conditioners and their ingredients. The first tier of testing utilized the Organisation for Economic Co-operation and Development (OECD) QSAR Toolbox to perform an in silico evaluation of the skin irritation potential of the product ingredients, and the second tier of testing utilized an OECD in vitro test to evaluate the skin irritation potential of each product. Thirty-two ingredients were evaluated using the OECD QSAR Toolbox profiler for the tier one analysis; nine ingredients received a structural alert for skin irritation/corrosion. In the tier two in vitro analysis, the evaluated cleansing conditioner products were all classified as non-irritants. These results provide evidence that use of the evaluated commercially available cleansing conditioners would not be expected to cause skin irritation among consumers. Additionally, this study demonstrates that the presence of structural alerts does not always accurately predict the safety of a product, as focused tier-based testing is necessary to comprehensively evaluate product safety. This study illustrates a tier-based safety assessment approach, applicable to a wide variety of health endpoints, which efficiently and adequately evaluates the safety of personal care and cosmetic products and their ingredients.