A CELL PIGMENTATION ASSAY SUITABLE FOR SCREENING OF COSMETIC RAW MATERIALS.

• TR Number: 218
• Authors: Costello, B. Collaborative Laboratories, Stonybrook, NY.

There is substantial interest in evaluating cosmetic raw materials for effects on melanin production. Since tyrosinase activity is considered rate limiting in melanogenesis, potential skin lightening materials are often screened by measuring their effects on this enzyme. However, melanogenesis involves a series of additional reactions, some of which may be amenable to modulation. In addition, the ability of an inhibitor to be effective in actual use can be limited by its skin and cell penetration properties. While panel testing is the only definitive method to determine efficacy under use conditions, large scale screening of potential actives in vivo is impractical and expensive. Therefore, a system was needed that would allow preliminary screening of actives and formulations prior to panel testing of only the most promising materials. To address this problem, we’ve experimented with a tiered in vitro screening system that incorporates a cell-based whitening/tanning assay as an intermediate between initial tyrosinase inhibition screening and an in vitro test using epidermal equivalent tissues that contain active melanoacytes (Melanoderm).