Abstract
The interaction of dodecyl betaine (C 12-Bet)/sodium dodecyl sulfate (SDS) mixtures at different mole fractions of the zwitterionic component ( X zwitter) with liposomes modeling the stratum corneum (SC) lipid composition were investigated. Liposomes were formed by a lipid mixture of 40% ceramides, 25% cholesterol, 25% palmitic acid and 10% cholesteryl sulfate. The surfactant/lipid molar ratios ( R e) and the bilayer/aqueous phase partition coefficients ( K) were determined at two sublytic levels (50 and 100% CF release) by monitoring the increase in the fluorescence intensity of liposomes due to the 5(6)-carboxyfluorescein (CF) released from the interior of vesicles. The fact that the free surfactant concentrations were always lower than their critical micelle concentrations suggests that the liposomes–surfactant sublytic interactions were mainly ruled by the action of surfactant monomers. At the two interaction levels studied the surfactant mixture for X zwitter=0.6 showed the highest ability to alter the release of the CF entrapped in the interior of vesicles (lowest R e values), whereas that for X zwitter=0.4 showed the highest degree of partitioning into liposomes or affinity with these structures (highest K values). Different trends in the interaction of these mixtures with SC lipids and phosphatidylcholine (PC) liposomes were observed when comparing the present R e and K parameters with those reported for PC ones. Thus, whereas SC lipid liposomes were more resistant to the action of C 12-Bet/SDS mixtures, the partitioning of these mixtures into SC lipid bilayers was always greater than that reported for PC ones.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call