Intracellular delivery mediated by an ethosomal carrier

The goal of this work was to investigate the efficiency of transcellular delivery into Swiss albino mice 3T3 fibroblasts of molecules with various physico-chemical characteristics from ethosomes, phospholipid vesicular carriers containing ethanol. The probes chosen were: 4-(4-diethylamino) styryl-N-methylpyridinium iodide (D-289), rhodamine red dihexadecanoylglycerophosphoethanolamine (RR) and fluorescent phosphatidylcholine (PC*). The penetration of these fluorescent probes into fibroblasts and nude mice skin was examined by CLSM and FACS. CLSM micrographs showed that ethosomes facilitated the penetration of all probes into the cells, as evident from the high-intensity fluorescence. In comparison, when incorporated in hydroethanolic solution or classic liposomes, almost no fluorescence was detected. The intracellular presence of each of the three probes tested, was evident after 3 min of incubation. Furthermore, with ethosomal D-289, fluorescence was also seen in the fibroblast nucleus. Enhanced delivery of molecules from the ethosomal carrier was also observed in permeation experiments with the hydrophilic calcein and lypophilic RR to whole nude mouse skin. Calcein penetrated the skin to a depth of 160, 80 and 60 mum from ethosomes, hydroethanolic solution and liposomes. respectively. Maximum fluorescence intensities measured for RR delivered from ethosomes, hydroethanolic solution and liposomes were 150, 40 and 20 AU, respectively. Fibroblast viability tests showed that the ethosomal carrier is not toxic to the cultured cells. (C) 2001 Elsevier Science Ltd. All rights reserved.