Permeabilita a mikrostruktura modelových lipidových membrán stratum corneum: srovnání nehydroxylovaných a (R)- a (S)-α-hydroxylovaných ceramidů

• Main Author: Šilarová, Michaela
• Other Authors: Vávrová, Kateřina
• Format: Dissertation
• Language: Czech
• Published: 2016
• Online Access: http://www.nusl.cz/ntk/nusl-344703

Ceramides are lipid components in the uppermost layer of the skin, stratum corneum and they are essential for correct function of a skin barrier. In the stratum corneum, ceramides with cholesterol and free fatty acids are in equimolar ratio. Ceramides contain sphingoid bases, which are amino alcohols sphingosine, phytosphingosine, dihydrosphingosine or 6- hydroxysphingosine. These sphingoid bases are N-acylated by non-hydroxylated, α- hydroxylated or ω-hydroxylated fatty acid, mostly by lignoceric (C24) acid. The aim of this work was to study the permeability and microstructure of the model membranes containing non-hydroxylated ceramides. Moreover, we aimed to study the effect of additional α-hydroxyl group in ceramides including the effect of stereochemistry in position 2. We prepared model membranes based on Cer, free fatty acids (C16-24), cholesterol and a small amount of cholesteryl sulfate (5 wt%). We investigated four permeability markers: electrical impedance, water loss through the membrane, flux of theophylline and flux of indomethacin. The microstructure and miscibility of ceramides with other lipids were studied by infrared spectroscopy and X-ray powder diffraction. The results from experiments showed some differences between ceramides. For example the effect of the type of sphingoid...