Charge influence of liposome on transdermal delivery efficacy

Abstract

To investigate the charge influence of the drug delivery system, cholesterol analogues, either with cationic, 4-cholesterocarbonyl-4′-(N,N,N-triethylamine butyloxyl bromide) azobenzene (CAB), or the neutral, 4-cholesterocarbonyl-4′-(N,N-diethylamine butyloxyl) azobenzene (ACB) were synthesized and combined in liposomal membranes respectively. CdTe quantum dots (QDs) were loaded into the vesicles as the fluorescence probe to trace the transdermal delivery processing on the nude mouse dorsal skin. Cellular uptake of QDs by NIH 3T3 cells was also studied. The result showed that the cationic liposome facilitated the internalization of loaded QDs into cells and distributed in cytoplasm area within a 1 h incubation. Moreover, in contrast to neutrally charged liposomes, the cationic liposome promoted transdermal delivery of loaded QDs through the skin. In 2 h, cationic liposomes delivered QDs to the upper epidermis, whereas QDs in neutrally charged liposomes still remained on the skin surface which had no obvious facilitation. The retentions of neutrally charged liposome loaded QDs in the epidermis after 8 h, were similar to the naked QDs which were used as control. On the other hand, although in low amounts, the cationic liposomes delivered QDs into vascular dermis at 12 h, helped the diffusion of QDs to the dermal layer.