Skin irritation: Reference chemicals data bank

A list of 176 chemicals, all of high or consistent purity and stable on storage, has been developed using available comprehensive in vivo rabbit skin irritation data. No new in vivo testing was conducted to qualify a chemical for inclusion in the list. The chemicals were tested undiluted in in vitro studies, apart from those chemicals where high concentrations could be expected to cause severe effects. The in vivo data were generated in studies carried out since 1981 according to OECD Test Guideline 404 and following the principles of Good Laboratory Practice. The data were obtained from tests normally using at least three rabbits evaluated at the same time, involving application of 0.5 g or 0.5 ml to the flank under semi-occlusive patches for 4 hr, and in which observations were made at least 24, 48 and 72 hr after removal of the patch. The chemicals represent a range of chemical classes [acids, acrylates/methacrylates, alcohols, aldehydes, alkalis, amines, brominated derivatives, chlorinated solvents, esters, ethers, fatty acids and mixtures, fragrance oils, halogenated aromatics, hydrocarbons (unsaturated), inorganics, ketones, nitriles, phenolic derivatives, S-containing compounds, soaps/surfactants, triglycerides] and different degrees of irritancy. They are ranked for skin irritation potential on the basis of a 'primary irritation index'. These chemicals could be used in validation tests of promising alternatives to the in vivo rabbit skin irritation/corrosion test. This is an essential step in the progression to regulatory acceptance of alternative procedures.