An index to the literature on structure-activity correlation methods was prepared and is available through NTIS (PB-240 658). A study of each of the major methods was made to determine requirements for application to toxicity data. Simultaneously a study was made of available toxicity data and of physical-chemical properties shown to be useful in correlation studies. These evaluations suggested that the structural fragments contained in chemical structures should be considered in structure-activity relationship studies as well as the n-octanol partition coefficients. A prototype toxicity data base was selected from the 1974 Toxic Substances list for 687 compounds for which oral LD50 values were reported in the rat or mouse. The use of discriminant and multiple regression analyses following preliminary clustering gave useful results, but a new extension of the method called 'substructural analysis' was used to predict the LD50 values in the rat. This method can readily be adapted to computer operation, and is recommended for extension to other sets of toxicity data.

"May 1976." "Contract no. 68-01-2657."