Differences in the distribution of steroids in sterol-containing liposomes: A study by liposome electrokinetic chromatography

This study was conducted to investigate possible differences in the interactions of some selected steroids based on their distribution coefficients with cholesterol- or ergosterol-rich liposomes. Structurally cholesterol and ergosterol have very close resemblance to each other and generally it is thought that they behave in a similar manner. In this work we will show that this is not the case. Liposome electrokinetic chromatography (LEKC) was selected as the methodology for estimating the interactions between the steroids and the liposomes and for calculating the distribution coefficients. Apart from the distribution coefficients, the interactions were also studied with a response surface methodology and exploratory regression analysis. Both graphical and statistical analysis confirmed that there is an obvious difference in the interactions between the studies steroids and the cholesterol- or ergosterol-rich liposomes, and even a minute change in the sterol content had a significant impact on the interactions. The study demonstrates the flexibility and efficacy of LEKC for studying analyte-lipid membrane interactions, and for investigating taylor-made liposome systems.