Development and Evaluation of Hydrogel-Based Sulfasalazine-Loaded Nanosponges for Enhanced Topical Psoriasis Therapy

Background: The low solubility and poor skin permeability of sulfasalazine (SLZ) present significant challenges for its effective topical delivery. The objective of the current investigation is to formulate a hydrogel-based SLZ-loaded cyclodextrin nanosponge for topical therapy in psoriasis. Methods: SLZ-loaded nanosponges were prepared by the melt polymerization method and evaluated for physiochemical characteristics, drug release, and cytocompatibility. The selected nanosponges (SLZ-NS4) were transformed to hydrogel and further evaluated for rheology, texture, safety, skin permeability, and in vivo for anti-psoriatic effect in mouse tail and imiquimod-induced psoriasis-like inflammation models in mice. Results: Physiochemical data confirms nanoscale architecture, drug inclusion in nanosponges, crystalline structure, and formulation stability. The release profile of SLZ-NS4 revealed sustained release behavior (22.98 ± 2.24% in 3 h). Cytotoxicity assays indicated negligible toxicity against THP1 cells, resulting in higher viability of cells than pure SLZ (p < 0.05). The HET-CAM assay confirmed the safety, while confocal laser scanning microscopy demonstrated deeper skin permeation of SLZ. In the mouse tail model, a remarkable decline in relative epidermal thickness, potential improvement in percent orthokeratosis, and drug activity with respect to control was observed in animals treated with SLZ-NS4 hydrogel. The efficiency of the developed SLZ-NS4-loaded hydrogel in treating psoriasis was confirmed by the decline in PASI score (81.68 ± 3.61 and 84.86 ± 5.74 with 1 and 2% w/v of SLZ-NS-HG). Histopathological analysis and assessment of oxidative stress markers revealed the profound anti-psoriatic potential of the fabricated SLZ-NS4 hydrogel. Conclusions: These findings highlight the profound potential of the developed delivery system as an effective topical therapy for psoriasis.