Effects of Lipid Compositions on Thermo-sensitivity of Stratum Corneum Lipid Liposomes

Abstract

The effects of lipid compositions on thermo-sensitivity of stratum corneum lipid liposomes (SCLL) were investigated. SCLL were prepared with ceramide (CE), palmitic acid (PA), cholesterol (CH) and cholesterolsulfate (CS). In order to estimate the contribution of each lipid to stability of these liposomes against changes of temperature, SCLL were prepared with changing the composition of each lipid and the leakages of a trapped probe (carboxyfluorescein ; CF) from these liposomes were measured at various temperature. The leakage from SCLL with low molar CH content increased with temperature, significantly at and above their gel-liquidcrystal transition tempareture (Tc). However, SCLL with low CE or PA content scarcely leaked out CF in the experimental condition. The particle size of SCLL with low CH content increased also markedly at and above their Tc. In addition, the increase of the microfluidity and degree of fusion of these liposomes were observed on the similar temperature range to leakage phenomena. These results suggest that the phase transition of membrane might affect thermo-sensitivity of SCLL and the cholesterol content plays a crucial role on thermal stability of SCLL especially, the phase transition and concomitant leakage of trapped marker compounds.