Both new in vitro eye assays are meant to help scientists establish which chemical ingredients do not need to be labeled for eye irritation or damage.
Test number 491
The first new testing guideline is for a short, five-minute exposure test and relies on cultured rabbit cornea cells. The organization prescribes a quantitative assessment of both cytotoxicity and cell viability following quick chemical exposure.
Then, following the United Nations’ international system for classifying chemicals as hazardous (or not), “a test chemical is classified as UN GHS Category 1 when both the 5% and 0.05% concentrations result in a cell viability smaller than or equal to 70%,” according to the abstract for test number 491.
“Conversely, a chemical is predicted as UN GHS No Category when both 5% and 0.05% concentrations result in a cell viability higher than 70%.”
Test number 492
The OECD’s second new eye irritation experiment is called a reconstructed human cornea-like epithelium test method.
This test “evaluates the ability of a test chemical to induce cytotoxicity in a RhCE tissue construct, as measured by the MTT assay,” according to the abstract. And notably, “colored chemicals can also be tested by use of an HPLC procedure.”
Once put through the test, chemicals that diminish tissue viability below 60% do not need to be labeled following the UN’s classification system.
Rabbit skin substitutes
Four skin irritation tests already published by the OECD were updated earlier this summer. Those “alternatives to the rabbit test for skin irritation…further expands the use of the methods,” explains ChemicalWatch.com in a blurb about the testing protocol updates.
This summer, legislation to end testing on animals was introduced in the US. Speaking on behalf of the Human Society International campaign to support such regulation, Claire Mansfield, director of that group’s #BeCrueltyFree project, told the press, “testing cosmetics chemicals for lipstick and shampoo on live animals isn’t just morally indefensible; it also makes poor scientific sense because these animal tests have never been proven reliable to assure human safety.” (Read that news from Cosmetics Design here.)
As more governments worldwide move closer to banning cosmetics ingredient testing, standardized protocol like these from the OECD help the beauty industry stay the course with confidence.