Dermal Test Method Evaluations
Regulatory agencies require testing to identify dermal corrosives (substances that can cause burns and permanent scarring to the skin) and irritants (substances that can cause reversible skin damage). Results of these tests are used to label chemicals so that users can take appropriate safety precautions; to determine appropriate packaging requirements; and to develop safe handling procedures for chemical spills.
In traditional dermal corrosion and irritation tests, a test substance is applied to the skin of a laboratory animal. ICCVAM has evaluated four non-animal (in vitro) alternative test methods for identifying corrosive substances. ICCVAM also contributed to the development of test guidelines for similar methods to identify potential dermal irritants. Descriptions of these activities and links to more information can be found below.
At the request of the U.S. Environmental Protection Agency, ICCVAM established performance standards for in vitro test methods for dermal corrosives. These performance standards were based on ICCVAM evaluations of in vitro methods to identify potential dermal corrosives; they can be used to evaluate test methods based on similar scientific principles that measure or predict the same biological or toxic effect. Testing criteria from the ICCVAM performance standards were included in updates of test guidelines for in vitro test methods issued by the Organisation for Economic Co-operation and Development.
The European Centre for the Evaluation of Alternative Methods (ECVAM) conducted validation studies of three in vitro methods to identify dermal corrosives: EpiDerm, EPISKIN, and the rat skin transcutaneous electrical resistance assay. ECVAM concluded that these methods were able to distinguish between corrosive and noncorrosive chemicals for all of the chemical classes considered. ICCVAM conducted an evaluation of the ECVAM studies and all other available data on these methods, and recommended their use in a weight-of-evidence approach for assessing the dermal corrosion potential of chemicals as part of an integrated testing scheme. In this approach, chemicals identified as corrosive with these tests can generally be classified without further animal testing.
An ICCVAM-sponsored independent peer review panel met in January 1999 to evaluate the Corrositex assay for the identification of potential dermal corrosives. The panel concluded that, for certain testing circumstances, Corrositex is useful as a stand-alone assay for evaluating the corrosivity of acids, bases, and acid derivatives. The panel also concluded that, in other testing circumstances and for other chemical and product classes, Corrositex may be used as part of a tiered assessment strategy. Finally, the panel noted that Corrositex offers advantages with respect to animal welfare considerations.