Draize Eye Scores and Eye Irritation Thresholds in Man Combined into one Quantitative Structure-Activity Relationship

Draize eye scores (DES) for 37 pure organic liquids have been converted into scores for the corresponding vapours, DES/P(o), where P(o) is the liquid vapour pressure in ppm at 298K. It is shown that there is a constant difference (0.66) between values of log(DES/P(o)) and log(1/EIT) where EIT is the eye irritation threshold in ppm of eight vapours towards human subjects. The 37 log(DES/P(o)) values can be combined with 17 log(1/EIT) values to give one quantitative structure-activity relationship, [Formula: see text] where R(2) is an excess molar refraction, pi(2)(H) is the compound polarizability/dipolarity, Sigmaalpha(2)(H) and Sigmabeta(2)(H) are the compound hydrogen-bond acidity and basicity, and L(16) is the gas-hexadecane partition coefficient. The number of data points is n, the correlation coefficient is r, the standard deviation is sd, and F is the F-statistic. LogSP is then either [log(DES/P(o)) - 0.66], or log(1/EIT). It is suggested that equation i can be used to predict eye irritation of organic vapours and pure liquids as eye irritation thresholds.