Estimation of chromatographic lipophilicity of bile acids and their derivatives by reversed-phase thin layer chromatography.

The main goal of this study was to estimate the lipophilicity and investigate the molecular mechanism of retention of bile acids and their derivatives in order to find an objective manner of quantitative comparison of different chemically bonded stationary phases for high performance TLC in terms of their (dis)similarities. Highly significant correlations were obtained between different experimental indices of lipophilicity (R(M0), S and the scores corresponding to the first principal component) estimated on CN(F254s) and RP-18(F254s) and some computed log P values that combine electronic and topological aspects. The most statistically significant quantitative structure-property relationship models, using descriptors from Dragon software, multiple linear regression and genetic algorithm, were also obtained in the case of CN(F254s) and RP-18(F254s) stationary phases. Cross-validation suggests a good reliability of the results. The contribution of 2D and 3D descriptors, which are related to atomic mass, together with reactivity parameters such as polarizability and electronegativity seem to control the chromatographic mechanism (lipophilicity) on all stationary phases.