Quantitative Structure-Activity Relationships (QSAR) are computer based tools that allow the estimation of chemical properties and toxicity based on a chemical's structure rather than from doing animal testing. QSARS, and their more qualitative cousins, SARs, are commonly used as screening tools to determine whether animal testing is needed. They are routinely used by the USEPA to assess premanufacture notice (PMN) submissions for new chemicals, which generally have very little actual testing data included. With the advent of REACH, the EU has also shifted to a greater acceptance of SARs and QSARs in lieu of actual laboratory testing.
To this end the European Chemicals Agency (ECHA) has made various QSAR tools developed by industry and governments available to companies registering chemicals under the REACH chemical registration law that went into force in 2007. ECHA has now released an updated, Version 2.2, of the "OECD QSAR Toolbox" for "grouping chemicals into categories" and "to fill data gaps by read-across, trend analysis and to assess the (eco)toxicity hazards of chemicals." The goal is to provide data for decision-making while reducing costs and unnecessary vertebrate animal testing.
According to ECHA, users of the QSAR Toolbox can:
- Identify analogues for a chemical, retrieve experimental results available for those analogues and fill data gaps by read-across or trend analysis;
- Categorise large inventories of chemicals according to mechanisms or modes of action;
- Fill data gaps for any chemical by using the library of (Q)SAR models;
- Evaluate the robustness of a potential analogue for read-across;
- Evaluate the appropriateness of a (Q)SAR model for filling a data gap for a particular target chemical;
- Build (Q)SAR models.
More information on the
OECD QSAR Toolbox can be found here.
