^{Chromatographic retention factor obtained on immobilized keratin stationary phase - what molecular properties does it encode?}

^{Chromatographic retention factors (log k}_KERATIN ^{) of 33 molecules were obtained on an immobilized keratin stationary phase by Turowski and Kaliszan (J. Pharm. Biomed. Anal. 15, 1997, 1325-1333). Their objective was to develop a novel stationary phase that could be used to investigate the skin permeability coefficient of solutes (log K}_p^{) in vitro. However, log k}_KERATIN ^{is not a sufficiently good predictor of skin permeability coefficient to be used as a sole descriptor in log K}_p ^{models. Turowski and Kaliszan reported that this descriptor can be used combined with the chromatographic retention factor obtained by Immobilized Artificial Membrane chromatography (log k}_IAM^{) and the results of log K}_p ^{predictions using multiple linear regression (MLR) models are moderately satisfying.}

^{In this study the values of log k}_KERATIN ^{obtained by Turowski and Kaliszan were correlated with a set of descriptors calculated using SwissADME software. It was discovered that log k}_KERATIN ^{encodes primarily lipophilicity, solubility and molecular size descriptos, which are important factors governing the ability of compounds to cross the skin barrier. On the other hand, log k}_KERATIN ^{does not correlate with polar surface area (PSA) and the molecule's ability to form hydrogen bonds - which are important properties in the context of solutes' skin permeability.}

^{It was concluded that log k}_KERATIN ^{could be used as a descriptor in MLR models of log k}_p ^{in combination with other parameters , such as PSA or H-bond descriptors.}