Development of elastic liposomes of caffeine for the treatment of cellulite

Abstract

In this study, caffeine elastic liposomes were developed for cellulite treatment by using the combination of surfactant and ethanol. The elastic liposomes studied consisted of phosphatidylcholine as the structural lipid, Span® 80 or Tween® 80 of the same molar ratio (5-10% w/w and 15-25% w/w of total lipid, respectively) as the edge activator and various concentrations of ethanol (5-25% v/v). The effects of type and amount of surfactants and concentration of ethanol on physical properties i.e., vesicle formation, size and size distribution and elasticity of blank liposomes were investigated. The blank liposome formulations with highest elasticity of each surfactant were selected to prepare the caffeine-containing elastic liposomes. These elastic liposomes were characterized for physical properties including entrapment efficiency and physical stability. The skin delivery of caffeine from the chosen elastic liposome formulations were carried out in vitro with modified Franz diffusion cells under the non-occlusive condition using newborn pig skin as the model membrane. The results showed that the complete vesicle formation was observed at low ethanol concentrations (5-15% v/v). The vesicle size of liposomes composed of Span® 80 and Tween® 80 was in the range of 5.84-8.08 µm and 3.73-5.27 µm, respectively. The combination of surfactant and ethanol showed significant effects on physical properties of elastic liposomes. The elasticity of liposomes containing Span® 80 and Tween® 80 was in the range of 27.07-79.86% and 8.44-15.74%, respectively. The formulations with highest elasticity, S7.5_5 with Span® 80 7.5% w/w and ethanol 5% v/v and T20_5 with Tween® 80 20% w/w and ethanol 5% v/v, were chosen to load caffeine. In general, physical properties of caffeine elastic liposomes were similar to the corresponding blank liposomes. However, caffeine loading decreased the elasticity of caffeine-entrapped elastic liposome formulations by approximately 20-30% compared to that of the blank elastic liposomes. The elasticity values of the caffeine-loaded elastic liposome formulations S7.5_5 and T20_5 were 53.46±8.63% and 11.93±0.46%, respectively. The entrapment efficiency values of S7.5_5 was lower than that of T20_5 (35.05±0.60 and 41.31±3.32% w/w, respectively). Skin permeation from S7.5_5 and T20_5 were significantly higher than that from the hydro-alcoholic solution used as the aqueous phase of these elastic liposomes. However, despite the profound difference in elasticity between the 2 formulations, no significantly differences were seen in most permeation parameters studied. The only significant difference detected was the enhancement factor of caffeine amount in the skin, the mean of which was almost doubled for the S7.5_5 formulation when compared to the T20_5 formulation.