INTER-AND INTRALABORATORY REPRODUCIBILITY OF A THREE DIMENSIONAL HUMAN EPIDERMAL MODEL – EPIDERM.

EpiDerm™ is a model of the human epidermis grown from normal human epidermal keratinocytes (foreskin-derived) seeded onto Millicell® CM (Millipore Corp., Bedford, MA) cell culture inserts. The inserts are placed at the air/culture medium interface allowing the cells to differentiate into a three dimensional model which consists of a basal layer of epidermal keratinocytes covered by a stratum spinosum and stratum granulosum and ultimately a well-defined stratum corneum. Solid and liquid test materials can be placed directly on the stratum corneum to determine their potential toxicity. Scientists at Microbiological Associates and MatTek Corp. investigated whether the model would be useful for routine dermal toxicology testing by examining lot-to-lot variability, intra-, interlaboratory variability and the effect of international shipping. Assays were conducted using both EC-50 (concentration of test material which reduces viability to 50%) and ET-50 (exposure time which reduces viability to 50%) protocols using pure surfactants and surfactant-containing formulations. Scientists found a good correlation for the results of three different laboratories. They also observed a strong relationship between the in vitro scores and the results of clinical irritation testing. The reproducibility and robustness of the system indicate that it may prove to be a useful model for testing dermal irritation.

Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Dermal, Dermal irritancy, Dermal irritancy testing, Dermal irritation, EpiDerm, Reproducibility, Reproducible, Skin irritancy, Skin irritation, Surfactants, Viability