A Comparative Study of the Molecular Lipophilicity Indices of Vitamins A and E, and of Some Precursors of Vitamin A, Estimated by HPLC and by Different Computation Methods

摘要

Lipophilicity indices for vitamins A and E, and for some precursors of vitamin A, have been determined for the first time by reversed-phase high-performance liquid chromatography (RPHPLC) on C-18 and C-8 columns. For each column the mobile phases were methanol-water mixtures with methanol in volume proportions from 86 to 90% (v/v) in 1% steps. The regression correlation coefficients obtained for both stationary phases were excellent (usually >0.999). To compare the experimental lipophilicity estimated for the compounds by use of log k(w)', S, phi(0), the means of k' and log k', and the scores of k' and log k' corresponding to the first principal component, and log P values calculated by use of different computer software a correlation matrix was constructed. Better correlations were obtained in both cases between the mean of k' and the mean of log k', and scores corresponding to the first principal component obtained by applying principal-components analysis to the matrix of retention factors and computed log P values. The best correlations were found between the mean of k' and scores corresponding to the first principal component determined on C-8 and most of the computed log P values.