Collagen immobilised on silica derivatives as a new stationary phase for HPLC

Synthesis of new stationary phases containing covalently bound collagen has been described. Commercially available soluble collagen and the silica derivatives, aminopropylsilica (APS) and diol-silica, were used for the experiment. The products of synthesis were subjected to elemental analysis and to a 13C-NMR analysis to prove the presence of the covalently bound protein on the support's surface. The stationary phases were packed into the columns and introduced into an HPLC system. A series of diversified test compounds was analysed to elucidate the retention mechanism operating on the collagen column by means of the quantitative structure-retention relationship (QSRR) analysis. Chromatographic analysis of a series of selected compounds was performed for which human skin permeation data were available. Quantitative structure-activity relationship (QSAR) analysis was done to model the human skin permeation by employing of the chromatographic data determined on the collagen column. The newly obtained collagen phases were demonstrated to possess distinctive retention properties due to a combination of specific (polar) and hydrophobic solute-stationary phase interactions. The normal-phase retention mechanism seemed to prevail on the collagen phases. For the set of test solutes available the interactions with collagen appear to be of secondary importance for their ability to permeate human skin compared to their hydrophobicity and binding to keratin. None the less, the collagen columns may be of value to complete the chromatographic model of human skin permeation.