International – Everything you always wanted to know about in vitro toxicology for cosmetics

The Cosmetics Regulation 1223/2009 is the main regulatory framework for finished products when placed on the EU market. Cosmetic products must be safe for human health.

The safety is largely based on the security of the ingredients, and their toxicological profile has to be evaluated.

The determination of the toxicological profile of an ingredient is based on a series of toxicity studies and the major endpoints that may be relevant to assess are eye and skin irritation, skin sensitization, photo-induced toxicity and genotoxicity. For each one, different test methods may be used and, depending on the type of sample, some may not be suitable.

It is therefore not easy to navigate the complexity and multiplicity of tests available.

This article aims to propose a clear and simple approach for toxicological testing of cosmetic ingredients.

First, in order to be worldwide recognized and accepted, the methods used have to be internationally validated, preferably published in OECD Guidelines, and conducted in compliance with the GLPs. In addition, the regulation prohibits ingredients that have been subject to animal testing after 2013.

Eye irritation potential can be assessed with different validated methods: BCOP (OECD 437), ICE (OECD 438), FL test (OECD 460), RhCE test (OECD 492) or STE (OECD 491) for instance. But in the best case, these methods allow to classify the product as “corrosive” or “non-irritant”.

For mild or moderate irritancy there is no validated method and it is therefore recommended to use additional tests even if they are not fully recognized, such as Het-Cam or Neutral Red Release.

The combinations BCOP/Het-Cam or RhCE test/Het-Cam are the most frequently used.

For the skin irritation endpoint, validated OECD methods also exist: OECD 430, 431 and 435 for skin corrosion and OECD 439 for skin irritation. OECD 431 and OECD 439 are performed on reconstructed Human Epidermis (RhE)…