Influence of liposome composition on in vitro permeation of diosmin through human stratum corneum and epidermis

The aim of this paper was to improve diosmin skin permeation by means of liposome carriers. To evaluate the effect of liposome composition on drug skin permeation, fluid liposomes and rigid liposomes were prepared following the thin layer evaporation method and were characterized by light scattering to determine their mean size, size distribution and zeta potential. Differential scanning calorimetry (DSC) was used to investigate the interaction of such liposomes with a model of ordered lipid structure, namely dipalmitoylphosphatidylcholine (DPPC) biomembranes. Human stratum corneum and epidermis membranes were used for the in vitro evaluation of diosmin skin permeation from the various liposome formulations and from a commercial one. Investigated liposomes showed a mean size ranging from 350 to 580 nm, a zeta potential ranging from -4 to -46 mV and a percentage of encapsulation of ~95%. DSC experiments showed that lecithins presenting unsaturated acyl chains were able to elicit a fluidization effect on ordered lipid structures which decreased in the following order: palmitoyl-oleoyl-phosphatidylcholine>Phospholipon 80®≥ Phospholipon 90G®> Phospholipon 100G®>> Phospholipon 80H®. The thermotropic parameters were in good agreement with in vitro diosmin skin permeation. Diosmin-loaded palmitoyl-oleoyl-phosphatidylcholine or DPPC/oleic acid (1:1 molar ratio) liposomes provided the highest increase and improved in vitro diosmin skin permeation 9 and 10 times with respect to a commercial liposome formulation, respectively. In conclusion, fluid lecithin liposomes or vesicles made up of lecithin/oleic acid mixtures could be used as topical delivery systems to improve diosmin skin permeation.