RECONSTRUCTED HUMAN SKIN AS MODEL FOR LIPOSOME-SKIN INTERACTION

Reconstructed human skin was prepared from human keratinoblasts. After 1 week of cultivation at the air-liquid interface a stratified layer developed, similar to native human epidermis. Liposomes with an averag e diameter of 50 nm, made of phosphatidylcholine (PC), phosphatidylser ine (PS) and human stratum corneum lipids (hSCL) were applied on top o f this culture system. The rate of penetration through the reconstruct ed human epidermis was 1.38, 0.55 and 0.013 ng lipid h(-1) cm(-2) for PC, hSCL and PS liposomes, respectively. Electron microscopy and confo cal laser scanning microscopy showed that PS and hSCL liposomes aggreg ated at the skin surface, while PC liposomes remained homogeneously di spersed. Fluorescence measurements demonstrated that vesicles, made of native human stratum corneum lipids rapidly mixed with PS liposomes, weakly with hSCL liposomes and did not mix with PC liposomes. (C) 1998 Elsevier Science B.V. All rights reserved.