Ask a RIFM Scientist

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What is read-across, and how does it save animal lives?

Holger Moustakas, PhD

Read-across is a safety assessment approach in which study data on one chemical can be used as a proxy to support the safe use of a structurally similar chemical lacking study data. The Research Institute for Fragrance Materials (RIFM) has saved more than half a million animals through its use of read-across and other animal-alternative methodologies.

In places like the European Union, which forbid new animal testing for cosmetics and other consumer products, governmental agencies like the European Chemicals Agency (ECHA) encourage and help guide scientists using this innovative method when evaluating materials with limited study data.

Chemical clustering, a process of grouping sets of chemicals based on their relative chemical similarity, has helped identify appropriate read-across analogs when needed. RIFM has developed a three-tiered approach that provides a systematic way of searching for analogs that even scientists who may not be as familiar with chemical structures can successfully perform.

A full description of this tiered system was recently peer-reviewed and will be available soon via the open-access Fragrance Material Safety Resource Center.

Read-across is a powerful tool. However, scientists may not always be able to use a read-across analog to predict a target chemical’s effect on multiple areas of human health.

Each human health endpoint has different chemical considerations when looking for a read-across analog. For example, some endpoints focus on reactivity, while others must have a high degree of structural similarity. These differences are why RIFM scientists may identify several different read-across materials in a safety assessment of a single target material.

Senior Scientist Holger Moustakas, PhD, leads RIFM’s computational chemistry efforts, including read-across solutions.