William Stokes, D.V.M., the National Institute of Environmental Health Sciences' associate director for animal and alternative resources, said, "The old test requirements called for three animals for each chemical that is evaluated for skin corrosivity and dermal irritation. Since there are more than two thousand chemicals introduced each year, the substitution of Corrositex could save many laboratory animals in a year."

Skin corrosiveness testing is conducted to ensure that chemicals and products are properly labeled to alert consumers and workers to take precautions to prevent chemical burns to the skin. Corrosion is more serious than skin irritation and involves permanent damage to skin, usually with scarring.

In the new test, developed under the trade name Corrositex, a chemical or chemical mixture is placed on a collagen matrix barrier that serves as a kind of synthetic skin. Once it penetrates the barrier, the chemical causes a color change in a liquid detection system composed of indicator dyes that are sensitive to strong acids and bases at pH extremes. The time it takes for a test chemical to penetrate the barrier and produce a color change in the detection system is compared to a classification chart to determine corrosivity.

In order to develop a scientific consensus on the usefulness and limitations of the new test, panel members evaluated all available information and data to determine the extent to which the ICCVAM criteria for validation and acceptance of new test methods was addressed.

This is the second substitute test to be approved by federal regulatory agencies after an ICCVAM panel review. The first review resulted in the acceptance by regulatory agencies of a test called the Murine Local Lymph Node Assay th
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Contact: Bill Grigg
grigg@niehs.nih.gov
301-402-3378
NIH/National Institute of Environmental Health Sciences
20-Mar-2000