Skin irritation testing
OECD TG 439
For this test, 3D reconstructed human skin models are exposed to the test material for 1 hour. Afterwards models are rinsed and incubated for 24 hours. The next day, supernatant can be collected for analysis of cytokines (e.g. IL-1α, optionally). Viability is subsequently assessed using the MTT test (colorimetric assay). If remaining viability is > 50% the test material is non-irritant.
Prediction Model
| Mean tissue viability (expressed as % of negative control) |
in vivo prediction | |
| EPI-200-SIT | OECD TG No. 439 (adopted and updated 2019) |
|
| < 50% | irritant (I) (R38 or GHS category 2) |
requiring classification and labelling (GHS Category 1 or 2) |
| > 50% | non-irritant (NI) | non-irritant to skin (GHS no category, no labelling requirements) |
The Modified EpiDermâ„¢ SIT allows discrimination to be made between irritants of category 2 and non-irritants. The test does not discriminate between non-mandatory subcategories of the UN GHS, i.e. it does not distinguish between GHS category 2 and category 3 irritants.