Abstract
Systemic administration of methotrexate (MTX), widely regarded as one of the most effective treatments for psoriasis, poses significant challenges due to its high toxicity, limited solubility, and potential for adverse effects. Consequently, developing a topical form of MTX may offer a safer and more effective strategy for psoriasis management. Silk fibroin (SF), a protein-based biomacromolecule, has shown considerable promise as a nanocarrier for sustained and targeted drug delivery, owing to its exceptional physicochemical and biological properties. This study aimed to develop and characterize a novel drug delivery nanocarrier for MTX using SF nanoparticles modified with hyaluronic acid (HA) and to assess their potential for skin-targeted drug delivery with reduced transdermal permeation. The nanoparticles were thoroughly characterized, demonstrating a uniform particle size, high drug-loading capacity, pH sensitivity, and excellent slow-release properties. In vitro and in vivo experiments further indicated that these nanoparticles effectively reduced psoriasis-induced inflammatory responses, including erythema and scaling, by inhibiting keratinocyte proliferation and decreasing levels of pro-inflammatory cytokines. The inclusion of HA improved nanoparticle targeting, particularly through interactions with overexpressed CD44 proteins in psoriatic skin, resulting in enhanced methotrexate accumulation at the sites of inflammation and improved therapeutic efficacy. Our findings suggest that HA/SF nanoparticles loaded with MTX represent a promising, safe transdermal delivery system for the localized treatment of psoriasis.