EVALUATION OF TWO IN VITRO HUMAN SKIN EQUIVALENTS (THE EPIDERM™ AND SKIN²™ MODEL ZK1300) FOR ASSESSING THE SKIN IRRITATION POTENTIAL OF PERSONAL CARE PRODUCTS AND CHEMICALS.

Living, three-dimensional human skin substrates were used to assess the relative skin irritation potential of selected chemicals and prototype shampoo formulations. Scientists at Clairol Inc. and Thomas Stephens Associates exposed two full-thickness skin equivalent models (EpiDerm™ from MatTek Corp. and Skin2™ from Advanced Tissue Sciences, Inc.) topically to the test materials for periods ranging from 15 min. to 24 hrs. MTT reduction was measured as the mechanistic endpoint for cytotoxicity. Relative irritancy potential was based on comparisons of the estimated time to reduce cell viability by 50% or on comparative cytotoxicity at selected time points. The objective cytotoxicity (ET-50) results for the shampoos as measured in the in vitro models were then compared to subjective irritation results observed in vivo in a clinical repeat application soap chamber test. The in vitro human skin models appeared versatile in categorizing or ranking materials representing a broad irritancy spectrum (i.e. chemicals). At the end of the spectrum, the models were able to separate out the personal care products into three groupings which closely matched the in vivo groupings.

Cosmetic Personal Care Products, Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Cytotoxicity, Dermal irritancy, Dermal irritancy testing, Dermal irritation, Endpoints, MTT, EpiDerm, Irritants/irritancy assessment, MTT, MTT ET-50 tissue viability assay, MTT assay, Shampoo formulations, Skin irritancy, Skin irritation, Skin models, Viability