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Phototoxicity Introduction


Phototoxicity describes a reaction that occurs when exposure to a test material results in skin irritation when combined with UVA exposure. In vitro phototoxicity assays are economical alternatives to in vivo animal and human tests for the screening of raw materials, ingredients, pharmaceuticals, and final formulations.

Our in vitro phototoxicity assays are in vitro cytotoxicity assays which have been modified to include an additional UVA exposure step during test material exposure for the identification of photoirritating test materials. We currently offer two assays for assessing phototoxic potential:

  1. 3T3 NRU Phototoxicity (96-well cell-based assay)
  2. 3-D Reconstructed Human Epidermis Phototoxicity

Both tests evaluate potential phototoxicity based on the relative reduction in viability of cells exposed to the test material in the presence of UVA exposure, relative to treated cells in the absence of UVA exposure. These two assays can be used in a tiered approach during product development: the 3T3 NRU phototoxicity assay may be used to test ingredients, and the 3-D reconstructed human epidermis phototoxicity assay is used to test formulations in a skin exposure model. Click on an assay above to find out more about the individual assays, and how each is used.

At IIVS, a positive and negative control are run with each assay. Specialized protocols may be prepared as requested through consultation with the Study Director.

Select from the menu at left for more information about individual phototoxicity assays. Each assay section will include an overview, applications, and brief Step by Step procedures.