RP-HPLC Retention Data for Measuring Structural Similarity of Compounds for QSAR Studies

Abstract

A quantitative measure has been developed for characterizing the structural similarity of compounds on the basis of their reversed-phase liquid chromatographic retention data. Reversed-phase retention data (expressed by log k' values) of 59 compounds of various types (aniline, phenol, morphine, barbiturate, xantine, sulfonamide, steroid, benzoic acid derivatives) have been investigated as a function of organic modifier concentration (OP%) in the mobile phase. The effect of acetonitrile and methanol concentration in the mobile phase on the log k' values was measured. High correlation was found between the slope and the intercept values of the log k' vs OP% straight lines for only structurally related compounds. In view of these results, the correlation coefficient between the slope and the intercept values of the linear section of the log k' vs OP% straight lines is suggested as a measure of structural similarity of compounds with regard to their partition behaviour in a reversed-phase chromatographic system.