(Q)SAR Application Toolbox: General Information

As part of the OECD activities to increase the regulatory acceptance of (Q)SAR methods when data are lacking, the OECD has started the development of a (Q)SAR Application Toolbox as a means of making QSAR technology readily accessible, transparent, and less demanding in terms of infrastructure costs. The Toolbox will be created in two phases. The first version will emphasise technological proof-of-concept and it is scheduled to be released in March 2008.

What is the (Q)SAR Application Toolbox?

The Toolbox is a software application intended to be used by member countries, chemical industry and other stakeholders in filling gaps in (eco)toxicity data needed for assessing the hazards of chemicals. The Toolbox incorporates information and tools from various sources into a logical workflow. Crucial to this workflow is grouping chemicals into chemical categories.

What is a chemical category?

A chemical category is a group of chemicals whose physicochemical and human/health and/or environmental toxicological properties and/or environmental fate properties are likely to be similar or follow a regular pattern as a result of structural similarity. In the category approach, not every chemeical needs to be tested for every endpoint. Rather, the overall data for that category must prove adequate to support a hazard assessment. The overall data set must allow the estimation of the hazard for the untested endpoints. Data gap filing can be done using read-across from one tested chemical to an untested chemical. Detailed guidance on grouping of chemicals has also been published in the series on Testing and Assessment.

What is the key feature of the Toolbox?

The toolbox allows a user to systematically group chemicals according to the presence or modulation of a particular effect for all members of the category based on the presumption of a common chemical or toxicological mechanism or mode of action. In the same way, the Tooolbox is able to quickly evaluate all members of a category for common toxicological behaviour or consistent trends among important regulatory endpoint data.

Why the chemical categories approach?

The categories approach used in the Toolbox:

Shifts emphasis to intrinsic chemical activity
Allows for entire categories of chemicals to be assessed when only a few members are tested, thereby saving costs and animals
Enables defensible hazard assessment through mechanistic comparisons without testing

What tools are in the Toolbox?

The Toolbox estimates missing values by:

Read-Across, that extrapolates for an untested chemical from tested chemicals within a category
Trend Analysis, that estimates for an untested chemical from a "trend" (increasing, decreasing or constant) in effect within a category
(Q)SAR Models that estimate missing values from a statistical model for a category

Download the (Q)SAR Application Toolbox

The (Q)SAR Application Toolbox as well as instructions for installation and getting started can be downloaded here.

Note: the same download facilities are also available on the OECD website.