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TEST METHOD
In-vitro skin corrosion testing for biocides, chemicals and cosmetics
Skin corrosion refers to irreversible tissue damage in the skin. This testing is performed using the EpiDerm model, which utilizes Reconstructed Human Epidermis (RhE) according to OECD 431, an internationally recognized guideline for assessing the skin corrosion potential and classification of biocides, chemicals, and cosmetics—without the need for animal testing.
The diagram below provides a summary of the test method according to OECD 431.
Understanding OECD 431 Testing
Application areas
OECD 431 is specifically designed for the hazard identification of chemicals, biocides, and cosmetics that may cause skin corrosion.
Test Protocol
Step 1: 0.03 mL of the test sample is applied to the EpiDerm RhE tissue for exposure time of 60 minutes.
Step 2: The EpiDerm RhE tissues are rinsed with DPBS.
Step 3: 0.3 mL of MTT solution is added to each well and incubated for 3 hours. The formazan formed is then extracted using isopropanol.
Step 4: 0.2 mL of the extracted formazan solution is transferred to a 96-well plate, and the absorbance is measured at 570 nm.
Exposure Time and Conditions
The test substance is applied directly onto the Reconstructed Human Epidermis (RhE) for the duration of 2 fixed exposure times:
- 3 minutes
- 60 minutes
After exposure, the tissue is rinsed and incubated before assessing cell viability via MTT assay.
Passing Criteria
The product is classified based on cell viability after 3 minutes and 60 minutes of exposure.
- Corrosive: Cell viability is below 50% after 3 minutes of exposure.
- Sub-category 1A: Cell viability is below 25%.
- Sub-category 1B/1C: Cell viability is 25% or higher but below 50%.
- Corrosive: Cell viability is 50% or higher after 3 minutes but below 15% after 60 minutes.
- Non-Corrosive: Cell viability is 50% or higher after 3 minutes and 15% or higher after 60 minutes.
Next Step for Non-Corrosive Products
If the product is classified as non-corrosive, an additional skin irritation test is required to determine its potential to cause skin irritation.
**Disclaimer: NO ANIMAL TESTING. TECOLAB is committed to ethical and cruelty-free testing practices. We do not conduct any form of testing on animals and all our biocompatibility tests are performed on in-vitro models.
Need help with your testing requirements?
Have questions about this test method or your product? Our technical team is here to assist you.