Defining benchmarking in the context of safety assessment of personal care and cosmetic products using New Approach...

The concept of benchmark materials in the personal care and cosmetic industry is often based on the positioning of prototypes relative to the leading brand within a given product category. The main points of comparison are the market ranking, performance regarding consumers' perception, aesthetics, cost, complexity of the manufacturing process and patents covering the product and/or its components. Even though benchmark materials are often included when conducting safety tests of cosmetic and personal care products, the concept is rather loosely defined in toxicological profiling. The use of benchmarks becomes of particular interest when safety testing is based on New Approach Methodologies (NAMs) (in silico, in vitro or ex vivo technologies) that allow for toxicity ranking of the prototypes and provide mechanistic insights without having an established prediction model. It is therefore important to define the properties and performance of the benchmark materials to better guide the safety testing of candidate formulations. In this review manuscript we discuss the criteria to select benchmarks, and provide specific examples of such finished products incorporated in the safety assessment studies of a wide range of cosmetic and personal care product classes. We also discuss strategies using benchmarks to evaluate the predictive capacity of test systems and methodologies that do not rely on the use of animals for safety assessments.