Pickering emulsions stabilized with chitosan/gum Arabic particles: Effect of chitosan degree of deacetylation on the physicochemical properties and cannabidiol (CBD) topical delivery

Abstract

Pickering emulsions (PEs) have recently gained increasing attention as green carriers of bioactive agents due to their surfactant-free and eco-friendly nature. Herein, the effect of the degree of deacetylation (DDA) of chitosan on the properties of chitosan/gum Arabic (CH/GA) particles and PEs was investigated. CH/GA particles with a DDA of 96% (high DDA) and 78% (low DDA) were prepared. The contact angle of water drop for the CH/GA particles prepared with high and low DDA chitosan was 84.2° and 77.5°, respectively. The dynamic interfacial tension of the particles has shown lower values with high DDA chitosan. The high DDA PE formulation exhibited higher stability after two months of storage than its counterpart prepared with low DDA chitosan. The mean emulsion droplet size was 15.6 ± 4.3 µm and 21.1 ± 2.6 µm for PEs prepared with high and low DDA chitosan, respectively. Both PE formulations demonstrated shear thinning and elastic gel-like properties. The amount of cannabidiol absorbed by the stratum corneum, viable epidermis and dermis was significantly higher in both PE formulations than the permeated amount, but no significant difference was observed between the amounts absorbed from both formulations.