Improved in vitro and in vivo collagen biosynthesis by asiaticoside-loaded ultradeformable vesicles

The potentiality of ultradeformable vesicles as a possible topical delivery system for asiaticoside, a natural compound obtained from Centella asiatica was evaluated, because this compound exhibits collagen biosynthesis promoting activity. Ultradeformable vesicles were prepared by the extrusion technique; these vesicles were composed of Phospholipon 100® and different molar fractions of sodium cholate as the edge activator. The physicochemical properties of the ultradeformable vesicles were investigated through differential scanning calorimetry and light scattering techniques. The potential cyctotoxicity and biological activity of asiaticoside-loaded ultradeformable vesicles were evaluated on primary human dermal fibroblast cells by determining the extracellular lactic dehydrogenase activity, the cellular viability and the biosynthetic production of collagen. In vitro permeation experiments through human stratum corneum and epidermis membranes were also carried out. Ultradeformable vesicles having sodium cholate molar fraction of 0.2 proved to be the most suitable topical carriers for asiaticoside. A sodium cholate content of > 0.2 was observed to be cytotoxic probably due to its co-existence with other lipid aggregates, an example being mixed micelles. Asiaticoside-loaded ultradeformable vesicles with a sodium cholate molar fraction of 0.2 elicited the greatest degree of collagen biosynthesis in human fibroblasts. Ultradeformable vesicles provided the greatest in vitro skin permeation of asiaticoside showing a 10-fold increase with respect to the free drug solution and favoured an increase in in vivo collagen biosynthesis. Ultradeformable vesicles are therefore suitable carriers for the pharmaceutical and cosmetic application of the natural agent asiaticoside.