Quantitative Structure- Activity Relationships studies, initial

The actual evaluation of the possible hazards of chemicals and the risk to humans handling such chemicals is based on data obtained from animal studies. This approach is constantly under discussion in terms of the ethical use of animals and some difficulties in adapting animal data to humans. Thanks to years of research, a huge amount of data on chemicals already exists, and the availability of data banks means that it is easy to access. Nevertheless, many chemicals are still unclassified for safety, and much research still needs to be done. Over the last 3 or 4 years, some industry associations have launched programs focused on testing chemicals to cover the lack of safety information, namely ICCA and HPV initiatives. Furthermore, some theoretical new tools such as the family approach and the quantitative structure-activity relationship (QSAR) are now available. These approaches are now under validation processes, which hopefully will lead to their use for regulatory purposes. 

Quantitative Structure Activity Relationships. With the large number of compounds that has been synthesized and tested, it is surprising that several quantitative structure activity relationship (QSAR) analyses have not been attempted as a means of correlating those structural attributes and physicochemical parameters that significantly affect potency. At least one detailed QSAR study has been reported.(20.21) Initially the pertinent physicochemical parameters were obtained for each position where substituents were varied. Then the study was extended to multiple substituted analogues. The parameters evaluated included the original STERIMOL parameters L(l) for N-substituents at position 1 L(8) and B4(8) at position 8 steric influence at position 6, Es(6) hydrophobicity at position 7, x(7) and lipophilicity of the whole molecule, log P. Parabolic... 

The major value of the new Structure-Activity Relationship presented and developed by us [19] for (poly)alkene + OH reactions resides in its inherent predictive potential regarding the detailed primary-product distributions of such reactions. This is especially useful for quantitative assessments of the various possible OH-initiated degradation pathways of biogenic VOC, of which there is such a diversity and multitude that one can realistically hope to perform detailed experimental studies on only a few of them. 

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