An ascorbic acid delivery system based on (W1/O/W2) double emulsions encapsulated by Ca-alginate hydrogel beads

The aim of the present study was to develop ascorbic acid (AA)-loaded (W1/O/W2) double emulsions encapsulated by Ca-alginate hydrogel beads system (AA-HB) for efficient topical delivery. Some factors related to the stability and encapsulation efficiency of AA-HB were investigated. In addition, AA-HB were evaluated for storage stability, antioxidant activity, release characteristics, and skin permeation properties. The results showed that AA-HB had good stability when stored at 4 °C and 25 °C for 60 d. Compared with AA-loaded (W1/O/W2) double emulsions (AA-DE) and AA-water solution (AA-WS), the AA-HB had a more significant sustained-release effect on AA, while the antioxidant properties of AA in AA-HB were not affected. In vitro permeation study showed that the skin permeation of AA was promoted by the synergistic effect of double emulsions and hydrogel beads. Hence, the (W1/O/W2) double emulsions encapsulated by Ca-alginate hydrogel beads might be a promising delivery system for topical applications of AA.