PARTITION-COEFFICIENTS IN OCTANOL-WATER AND LIQUID-CHROMATOGRAPHIC BEHAVIOR OF 8 OXYGENATED TRITERPENES WHICH ARE PAIRED STEREO AND POSITIONAL ISOMERS

The chromatographic behavior of eight lanostanoid triterpenes, which a re four pairs of C-3 epimers and two pairs of C-3/C-15 positional isom ers, were determined by reverse-phase high performance liquid chromato graphy (RP-HPLC). In the mobile phase systems of acetonitrile-water-ac etic acid, methanol-water-acetic acid, and tetrahydrofuran-water-aceti c acid, these triterpenes showed a very good linear relationship betwe en capacity factors (k') and volume fractions of organic modifiers. Th e partition coefficients (Poet) of these triterpenes in 1-octanol/wate r and capacity factors (k') in RP-HPLC, when both expressed in logarit hm, correlated linearly. This study showed that RP-HPLC is an effectiv e method to evaluate the molecular hydrophobicity of multi-functional compounds which are stereo- and positional isomers.