Enhanced Phototoxicity screening Assay in Reconstituted Skin (EPARS)

In Vitro Toxicology

Background - Enhanced Phototoxicity screening Assay in Reconstituted Skin (EPARS)

MB Research Laboratories has developed and prevalidated an in vitro screening test for phototoxicity, EPARS, to replace current standard phototoxicity tests, like the ICCVAM accepted 3T3 Neutral Red Uptake Phototoxicity Test (3T3 NRU PT).

The phototoxic potential of chemicals, cosmetics, dietary supplements and pharmaceuticals are a major and growing concern with the diminishing protective o-zone layer and increasing cases of sundamaged skin.

Although the 3T3 NRU PT has been accepted by ICCVAM, EPARS is significantly superior to the 3T3 NRU PT viability test because it overcomes several limitations of the accepted test.

  • EPARS is based upon differentiated tissue models that closely parallels human skin morphology.
  • EPARS is constructed of human keratinocyte while the 3T3 NRU PT is conducted with monolayers of mouse fibroblast cells.
  • Unlike the 3T3 NRU PT, EPARS is not limited to testing media soluble test substances and allows for topical application directly on the tissues.


"EPARS: An In Vitro Phototoxicity Test Using Epidermal Tissue Models" - 2216KB
- An improvement on existing photo-cytotoxicity tests by (1) accommodating the topical application of test articles and (2) using a primary human cell-based tissue with a morphology that approximates the 3-dimensional characteristics of human skin.

Society of In Vitro Biology 2006 Abstract.

The project described was supported by grant number R44-ES-11927-02 from the National Institute of Environmental Health Sciences (NIEHS), NIH. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the NIEHS, NIH.