Encapsulation of Cannabidiol in Chitosan-Stabilized Argan Oil Nanoemulsion as a Potential Dermal Drug Delivery System for Psoriasis Treatment

Background: Cannabidiol (CBD), a non-psychoactive compound derived from Cannabis sativa, exhibits therapeutic potential for various conditions, including inflammation, pain, and skin disorders, making it a promising candidate for the topical treatment of psoriasis. However, its poor water solubility and instability limit its therapeutic efficacy. This study focuses on the development and characterization of CBD-loaded nanoemulsions using argan oil as the lipid phase, with and without a chitosan coating, which serves as a stabilizing and functional biopolymer. Methods: Nanoemulsions (NE) and chitosan-stabilized nanoemulsions (CS-NE), both without CBD (serving as controls), and CBD-loaded variants (CBD-NE and CBD-CS-NE) were prepared and characterized for their physicochemical properties, including pH, droplet size, polydispersity index (PDI), zeta potential (ζ-potential), and viscosity at various shear rates and temperatures. Stability was assessed over time, and drug release behavior was investigated through in vitro diffusion and ex vivo skin permeation studies, followed by kinetic modeling. Safety was evaluated through in vitro cytotoxicity assays using HaCaT keratinocyte cells, as well as in vivo toxicity studies using Caenorhabditis elegans (C. elegans). Results: The chitosan-coated formulations exhibited enhanced physical stability, nanoscale droplet size, a positive surface charge, and increased viscosity. Release studies demonstrated that CBD-CS-NE enabled controlled and sustained drug release, with a strong correlation to the Higuchi model, indicating diffusion-controlled permeation. Cytotoxicity assays indicated that CBD-CS-NE was non-toxic to cultured cells, while in vivo testing with C. elegans revealed sensitivity to chitosan-coated systems. Conclusions: These findings highlight the potential of CBD-loaded argan oil nanoemulsions, particularly those stabilized with chitosan, as potential topical delivery systems for managing psoriasis.