Hydrophobicity parameter from high-performance liquid chromatography on an immobilized artificial membrane column and its relationship to bioactivity

Abstract

There are numerous measures of hydrophobicity employed in the quantitative structure-bioactivity relationship studies. Individual bioactivity parameters may appear best predicted by the specific hydrophobicity parameters. Introduction of an original reversed-phase material, the immobilized artificial membranes (IAMs) opened new perspectives for bioactivity predictions in the case of the hydrophobicity-driven processes. Comparative studies of performance of the HPLC-derived hydrophobicity measures demonstrate the advantages of the IAM-derived hydrophobicity parameters in predicting the human skin permeation by non-ionizable agents as exemplified by steroid hormones. On the other hand, the skin permeation data of agents ionized at physiological pH appeared less dependent of the retention on IAMs. The IAM columns increase the means of characterization of various aspects of hydrophobicity. Their advantages over the slow equilibrium methods of hydrophobicity determination are the simplicity of operation and the suitability of the generated retention measures for predicting specific bioactivity parameters.