NEW EPIDERMAL MODEL FOR DERMAL IRRITANCY TESTING.

An interlaboratory comparison of EpiDerm™, a new model of human epidermis, was conducted using a range of anionic and non-ionic surfactants and surfactant-containing final formulations. The toxicity of the materials was estimated by MTT conversion, using both concentration (EC-50) and time (ET-50) protocols. A range of 16 compounds were tested on different production lots of EpiDerm following 1 and 2 day storage periods (post-shipping) at MatTek and at two independent testing laboratories (Microbiological Associates, US and Scotland). The EC-50’s and ET-50’s were compared and the least squares fit lines with resulting correlation coefficients (r) calculated. Correlation of in vitro results to human clinical chamber irritation and repeat handwash testing gave r values ranging from 0.977 to 0.993 and comparison of the results obtained in the independent laboratories with the site of manufacture was good (MA, US, r=0.84; MA, UK, r=0.90). The EpiDerm model appears to have utility in predicting clinically observed dermal irritation in vitro which appears to be reproducible in different laboratories even after transatlantic shipping, such that it is worthy of further investigation.

Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Dermal, Dermal irritancy, Dermal irritancy testing, Dermal irritation, Endpoints, MTT, EpiDerm, MTT, MTT ET-50 tissue viability assay, MTT assay, Reproducibility, Reproducible, Skin irritancy, Skin irritation, Surfactants