COMPARISON OF CORROSITEX AND EPIDERM IN VITRO SKIN CORROSION SCREENING ASSAYS TO IN VIVO CORROSIVITY RESULTS.

This study by researchers at Dow Chemical Co. demonstrated that MatTek’s EpiDerm human skin tissue equivalent gave near-perfect concordance with in vivo corrosivity data for a panel of 12 reference chemicals recommended in OECD Guideline 431. In this study, Dow Chemical scientists objectively compared a battery of chemicals in the EpiDerm™ (MatTek Corp., Ashland, MA) and Corrositex (InVitro International, Irvine, CA) in vitro corrosivity screens to existing in vivo data. EpiDerm consists of cultured, normal human epidermal keratinocytes in a differentiated epidermal model with organized basal, spinous and granular layers, and a stratum corneum containing intercellular lamellar lipid layers analogous to those found in vivo, Corrosivity is assessed as relative cytotoxicity at 3-min and 1-hr as the mitochondrial reduction of a tetrazolium salt. Corrositex uses a bio-barrier membrane comprised of a hydrated collagen matrix and supporting filter membrane on top of a vial filled with a chemical indicator dye, with corrosivity assessed according to breakthrough time. A panel of 12 reference chemicals recommended in OECD Guideline 431 for laboratory validation procedures was used [six corrosive: 1,2 diaminopropane; acrylic acid; 2-tert-butylphenol; potassium hydroxide; sulfuric acid; octanoic acid; and six non-corrosive: 4-amino-l,2,4-triazole; eugenol; phenethyl bromide; tetrachloroethylene; isostearic acid; and 4-methylthio-benzaldehyde], as well as 15 proprietary chemicals [nine corrosives and six non-corrosives in vivo, comprised of one alcohol, three organic acids, seven amines, two acrylic acid derivatives, and two halogenated herbicides]. EpiDerm exhibited 96% in vivo concordance (26 of 27), with 1 of 27 giving a borderline false negative for an organic acid. Corrositex exhibited 70% (19 of 27) in vivo concordance; with 3 of 27 false negatives (two organic acids and one halogenated herbicide), 2 of 27 false positives (both were amines), and 3 of 27 that didn’t qualify due to lack of reactivity with the indicator dye. Erroneous results weren’t restricted to false negatives, positives or by chemical class. One organic acid was a false negative for both in vitro assays, with the borderline EpiDerm result suggesting potential corrosivity in vivo. In conclusion, EpiDerm gave near-perfect concordance with in vivo corrosivity data.

1,2 diaminopropane; acrylic acid, 12 reference chemicals, 2-tert-butylphenol, 4-amino-l,2,4-triazole, 4-methylthio-benzaldehyde, Dermal corrosion, EPI-200, EpiDerm, Eugenol, In vitro corrosivity screens, In vivo data, Isostearic acid, Laboratory validation procedures, Mitochondrial reduction tetrazolium salt, Near-perfect concordance, OECD Guideline 431, Octanoic acid, Phenethyl bromide, Potassium hydroxide, Sulfuric acid, Tetrachloroethylene