3D living skin models: product development

The combination of effective testing and marketing gave Protect & Perfect a distinct advantage over the competition, ushering in a new age in the marketing of personal care products, with cosmetic and personal care companies receiving increased pressure to provide solid evidence to support claims of product effectiveness. However, as proving efficacy remains discretionary for cosmetic and personal care products, for many manufacturers the primary motivating factor for testing non-regulated skin care products remains financial. Therefore, although companies can no longer rely entirely on marketing claims, there is still some reluctance to invest in R&D activities to help develop the stronger claims that attract the attention of consumers, even though there are now many laboratory and clinical methods available. Also, while reliable quantitative in vitro and in vivo methods have been developed to support many common claims (i.e. increased hydration, reduction in spots, reduced appearance of wrinkles, etc.), there is often a discrepancy between what is meant by the product claim for the consumer compared to the cosmetic scientist.

The testing landscape

 The most obvious point of reference for evaluating the effectiveness of cosmetic and personal care products are studies using human volunteer subjects. However, the capital cost of instrumentation, recruiting suitable panels of volunteers and executing the study is beyond the means of many companies. Therefore, the process is commonly outsourced to specialist Clinical Research Organisations (CROs), which often have specialist expertise in certain types of study. While a properly designed and conducted clinical study is undoubtedly the pinnacle of the testing pyramid, the dual issues of cost and ethics restricts its use to the end of the development process. Earlier phases of development such as discovery, mode of action and efficacy studies are better served by in vitro laboratory testing using model systems which are more cost effective for screening purposes and allow much more extensive investigations than would be ethically acceptable using human subjects. The usefulness and predictability of in vitro test systems for cosmetic and personal care applications has been enhanced significantly in recent years by the development of sophisticated threedimensional living skin equivalent models as a stepping stone between simple in vitro laboratory assays and clinical studies. Therefore, the cosmetic and personal care industries have access to three distinct levels of efficacy testing for ingredient and product development (Table 1) within a testing continuum, with graded levels of cost, complexity and claims. With consumers and media no longer willing to accept advertised claims at face value without some confirmation and an increasing number of competing personal care brands producing similar products with similar benefits, verification of activity through testing is a cost-effective way to generate competitively advantageous consumer claims. Traditionally, the most successful brands at all price points are those that use R&D to generate advanced formulations and back up their products claims with scientific proof.