Immune response chemical barriers

There are several types of irritancy testing protocols that are used to comply with federal and international safety regulations. The classic Draize test was developed in 1944 to measure acute primary irritation. The test compound is applied in an occluded fashion to a clipped area of abraded and intact skin of at least six albino rabbits and evaluated 24 hr and 72 hr after patch removal. The degree of erythema and edema, ranging from one to four, is recorded to reflect severity of the irritation. Because these tests are occluded, irritancy is potentiated due to hydration, which reduces the skin barrier. The Draize test may be modified to assess sensitization by preexposing animals to a sensitizing dose of the study chemical and then rechallenging the animals at a later date to illicit the immune-mediated response. 

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