Measurement and prediction of hydrophobicity parameters for highly lipophilic compounds: Application of the HPLC column-switching technique to measurement of log P of diarylpyrazines

Article abstract of DOI:10.1021/js990112s

In the preparatory stage of structure-activity relationship (QSAR) studies of anti-platelet aggregant pyrazine derivatives, log P values (P: 1- octanol/water partition coefficient) of diarylpyrazines were measured by a newly developed HPLC column-switching technique. The system consists of two processes: (1) adsorption of the sample at the top end of a short precolumn, and then (2) quantifying the enriched analyte by a conventional analytical column. By using the log P values thus obtained, the correction factor for the steric hindrance caused by the vicinal diphenyl groups was estimated. The log k values (k; retention factor) were also measured with methanol-buffer (pH 7.4) eluents and related to log P. The eluent of 50% methanol content (M50) gave a good linear relationship over a wide range of log P (-0.3< log P < 5.2), indicating that log k(M50) parameter is useful for predicting the log P value.