QSAR of aliphatic amines using the embryotest with the zebrafish Danio rerio

Aims of the study: - previous studies with aliphatic amines and fish are mostly insufficient with regard to the existing database (heterogeneity of fish species used, test durations and recorded endpoints); - to determine the acute toxicity of selected aliphatic amines using the embryotest with the zebrafish Danio rerio; - to develop a Quantitative Structure-Activity Relationship (QSAR) describing and explaining the toxicity using several molecular descriptors. The toxicity of the primary and secondary amines could be described using the effective diameter and the lipophilicity (expressed as log KOW in a linear multiple regression model. The toxicity increased with increasing lipophilicity. Within this group no molecule with a effective diameter larger then 7 Å could be found and therefore, the membrane passage (< 9 Å) was not inhibited. For the toxicity of tertiary amines no multivariate model with acceptable correlation was found. Only a bilinear regression model with lipophilicity as parameter could be found. One possible explanation for this phenomenon is, that the larger molecules were inhibited due to their steric geometric and could not pass the membranes as well as targeting the embryos.