Abstract: Objective To establish ethosomes encapsulated with 5-Fluorouracil and to explore the inhibitory effects of 5-FU on human hypertrophic scar fibroblasts. Methods Ethosomes encapsulated with 5-Fluorouracil was prepared by Touitou method and was evaluated. Human hypertrophic scar fibroblasts were cultured in vitro, the penetration of the fluorescent probes into fibroblasts was examined by CLSM, and hydroalcoholic solution was set as control group. The effect of ethosomes encapsulating different concentration of 5-FU on fibroblast viability was tested by cell counting kit-8 (CCK-8), and the median inhibitory concentration (IC50) was calculated. The effect of ethosomes on fibroblast viability was tested by CCK-8. Results The particle size of 5-FU encapsulated ethosomes was (87.5 ±5.4) nm, the polydispersion index was 0.151 ±0.27, and the encapsulation efficiency of 5-FU was (10.03 ±2.12)%. CLSM micrographs showed that ethosomes facilitated the penetration of RhoB into the cell, as evident from the high intensity fluorescence. In comparison, when incorporated in hydroalcoholic solution, very weak fluorescence was detected. The optical density (OD) of unit area was calculated through the Image-Pro Plus 6.0 image analysis software, and the OD value of ethosomal group was distinguished higher than hydroalcoholic group (P<0.01). With the increase of the concentration of 5-FU, growth inhibition rate of fibroblast affected by 5-FU HA and 5-FU ES was gradually enhanced. The IC50 of 5-FU encapsulated ethosomes and 5-FU hydroalcoholic solution to fibroblasts were (9.2582±1.2329) μg/mL and (18.0352±2.3145) μg/mL, respectively, the difference between the two groups was distinguished (P<0.05). Meanwhile, ethosomal carrier was not toxic to the cultured cells. Conclusion Ethosomes can effectively enhance intracellular delivery of 5-FU, as a result can enhance the inhibitory effect of 5-FU on fibroblast viability. Meanwhile, ethosomal carrier was not toxic to the cultured cells. Ethosomes as percutaneous drug delivery carriers, are also a promising candidate for the delivery of biological and chemical compounds to cultured cells.

Key words: Ethosomes, 5-fluorouracil, Hypertrophic scar, Fibroblast, Intracellular delivery