Interaction of Liposomes with the Human Skin Lipid Barrier: hSclls as Model System — DSC of Intact Stratum Corneum and in Situ CLSM of Human Skin

Abstract

The interaction of liposomes with the human skin lipid barrier was studied by (i) physico-chemical analyses of lipid vesicles prepared from the complete mixture of human epidermal lipids, (ii) differential scanningcalorimetry of integral horny layers (strata cornea) before and after topical administration of phospholipid vesicles and (iii) confocal laser scanning microscopy of pieces of skin to which Rho-PE labelled DMPC-liposomes were applied. The data imply that the epidermal lipids of the human skin have at body temperature a high propensity of mixing if Ca²⁺ -ions are present, that intact liposomes do not penetrate into the viable epidermis but diffusing/mixing liposomal lipids disorder the complex structure of the upper intercellular lipid sheets thereby causing an increased hydration. The result is an enhancement of penetration of chemicals via the ‘polar and lipid routes'.