Dermal Irritation

Predict the potential of your test compound or xenobiotic to cause dermal irritation using our Skin Irritation Test (SIT). 

This test is performed according to the Organization for Economic Co-operation and Development (OECD) test guideline number 439 and allows for proper labelling of the test compound or xenobiotic according to United Nations Globally Harmonized System (UN GHS) Classification and Labelling of Chemicals.¹

Historically, dermal irritation was performed on rabbits using the Draize Skin Test.²  However, three dimensional human epidermis tissue equivalents have been developed and validated as replacements for the Draize skin test.  These 3D tissues are dermal epithelia grown from normal human keratinocytes and are extremely similar to native human epidermis, both metabolically and morphologically, including the stratum corneum.  In addition, the apical surface is direct contact with the air (tissue is fed basally) allowing for testing of almost all types materials, such as gels, creams liquids and powders, regardless of aqueous solubility.

Assay Overview

In this assay, MatTek EpiDerm™ tissues are exposed on the apical surface to neat (undiluted) test chemical for 30 minutes and the viability of the tissue is then determined via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.  This data is then normalized to the negative control and ocular irritation is determined based on the viability using the following table:

Additionally, the protocol can be adapted in order to assess irritation potency (mild, moderate, severe etc.) of test chemicals by determining the ET₅₀ over a 24 hour exposure period.

References

OECD (2015) OECD Guidelines for the Testing of Chemicals, Section 4. Test Guideline 439. In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method. Organization for Economic Co-operation and Development, Paris, July 28, 2015.
Draize J.H., Woodard G., and Calvery H.O. (1944). Methods for the Study of Irritation and Toxicity of Substances Applied Topically to the Skin and Mucous Membranes. J Pharm Exp Ther 82, 377-390.