Refinement of an in Vitro Test for the Identification of Skin Corrosive Chemicals

An in vitro test for predicting the skin corrosive potential of chemicals has been developed in this laboratory. In the test, chemically induced destruction of skin taken from young rats is measured as a fall in the transcutaneous electrical resistance as a result of an increased permeability to sodium and chloride ions through the skin. It is known that chemicals that do not induce direct tissue destruction, such as noncorrosive surfactants and organic solvents, can also decrease transcutaneous electrical resistance by virtue of their ability to solubilize lipids in the stratum corneum, thereby enhancing transcutaneous ion flow. We have compared various aqueous electrolyte solutions—NH4C1, NaHCO3, MgSO4, and Na2SO4 (all 154 mM)—with the standard NaCl electrolyte currently used for transcutaneous resistance measurements, in an attempt to reduce the frequency of false positive results due to noncorrosive (in vivo) surfactants and organic solvents. The results show that using magnesium sulphate as the elect...