INITIAL CHARACTERIZATION OF A NEW MODEL FOR OCULAR IRRITANCY TESTING.

A three dimensional, tissue culture construct, EpiDerm-SCA (EpiOcular™), based on neonatal foreskin-derived normal human epidermal keratinocytes (NHEK) is under development by MatTek Corporation. Cultured using serum free media in easily handled Millicell® CM (Millipore Corp.) cell culture inserts, the model allows application of liquid and solid test materials (potential ocular irritants) directly to the apical surface of these stratified, non-cornified cultures. Permeability measurements show the barrier function of the model to be significantly lower than MatTek’s cornified skin model, EpiDerm, and lipid analysis shows the ocular model to be lacking barrier lipids. From a toxicology standpoint, the ocular model is more sensitive than the skin model. In addition, an initial toxicology study was performed using the MTT assay with a graded series of 11 final formulation shampoos for which Draize ocular irritancy scores were available. The shampoos were dosed at 4 concentrations in duplicate wells (N=2), the average coefficient of variation was 9.55%. Further, the EC-50 values (effective concentration of test materials which reduces the MTT response to 50% of control cultures) when compared to non-washed Draize eye scores, had a correlation coefficient, r, of 0.885. In summary, the model’s physical-chemical nature is much more closely related to ocular tissue than to skin and its toxicological behavior appears to correlate with in vivo ocular results. Therefore, it is anticipated that the model will have broad applications for non-animal eye irritancy testing.

Barrier properties formation, Ceramides, Cosmetic Personal Care Products, Shampoo(s), Draize prediction model, Draize scores, Draize tests, Endpoints, MTT, EpiDerm, Eye irritation, Lipids, ceramides, MTT, MTT ET-50 tissue viability assay, MTT assay, Ocular irritancy testing, Ocular irritation, Ocular irritation testing, Pre-validation, Prediction model, Prevalidation, Profiles/Analyses, Skin models, cultured, Validation