Expert Reviews

Assessing Experimental Data

Before running any in silico models, the first step should be to search toxicity databases for appropriate laboratory results performed on the test material. Any results from a database search should contain sufficient information necessary to understand the adequacy of the study.104

In the following example, the mutagenicity of 4-pyridylamine is being assessed (shown in Figure 9.4). A bacterial reverse mutation assay may be used to assess mutagenicity as defined in oECD guideline 471.7 when assessing the mutagenicity of 4-pyridylamine, the first step is to identify whether any bacterial reverse mutation assay data are available, if the experimental design and results are available for inspection, and whether the study was performed according to the oECD 471 guideline. in this example a five-strain GLp assay was performed in a manner consistent with the guideline. since the study was adequately performed, no further in silico predictions need be generated, and it can be concluded that 4-pyridylamine is non-mutagenic from the laboratory data.

several issues can make retrieving experimental data challenging. Ап analysis of the study results may reveal deviations from standard test protocols. A database search might retrieve multiple study results for the same compound (or different forms of the same compound) from different laboratories, and those results might be conflicting. A critical assessment of the experiments should be considered and conclusions drawn. searching many individual public and commercial toxicity databases along with in-house databases can be time consuming. utilizing an intermediate database search service that searches many different sources simultaneously would save a great deal of time. For example, a single search of the Leadscope sAR Genetox database (as discussed in section 9.2.3) returns studies from more than 11 different sources.

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