LOT-TO-LOT VARIABILITY OF EPIDERM, AN EPIDERMAL MODEL FOR DERMAL IRRITANCY TESTING.

A model of the human epidermis, EpiDerm™, cultured from neonatal fore-skin-derived normal human epidermal keratinocytes (NHEK) was introduced by MatTek Corporation in April 1993. Using highly controlled tissue culture techniques, weekly batches of EpiDerm are produced and shipped domestically and internationally for dermal irritancy testing, percutaneous absorption studies, and basic skin research, amongst other uses. Histology, sterility and toxicological behavior are rigorously monitored on each batch which is shipped. Regarding histology, light microscopy evaluation of H&E cross sections show a reproducible, highly differentiated skin-like structure, both well-to-well (within an individual batch) and lot-to-lot. Regarding sterility of shipped EpiDerm, after 9 months of production batches, no contamination has been discovered on randomly selected EpiDerm held at MatTek and only a single customer on a single batch has reported evidence of contamination. Regarding the toxicological behavior as monitored using the MTT assay, the average well-to-well coefficient of variation (c.v.) for EpiDerm exposed to the negative control (ultrapure water) was 4.95% and the average c.v. for EpiDerm exposed to the positive controls (SDS and Triton X-100) over a range of concentrations was 9.65%. Lot-to-lot MTT values for the negative control have given a c.v. of 12.7% (N=39 batches) and the EC-50’s for SDS and Triton X-100 have given c.v.’s of 19.0% and 27.4%, respectively. Thus, EpiDerm appears to be highly reproducible, both structurally and functionally, and hence should be useful for toxicology and other in vitro skin related studies.

Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Dermal, Dermal absorption, Dermal irritancy, Dermal irritancy testing, Dermal irritation, Dermal penetration, Dermal permeation, Endpoints, MTT, EpiDerm, MTT, MTT ET-50 tissue viability assay, MTT assay, Percutaneous absorption, Percutaneous penetration, Reproducibility, Reproducible, Skin irritancy, Skin irritation, Sodium dodecyl sulfate (SDS), Surfactants, Transdermal, Triton X-100