Development and optimization of sulfasalazine loaded microemulsion for improved topical treatment of psoriasis.

BACKGROUND

Psoriasis is a persistent, chronic autoimmune skin disease that affects around 2% of the global population. Conventional therapies often exhibit limited efficacy, systemic side effects, and poor patient compliance due to long-term treatment needs.

MATERIALS &

METHODS

This study focused to develop and optimize a sulfasalazine-loaded microemulsion (SSZ-ME) for topical delivery to enhance skin penetration and therapeutic efficacy in psoriasis. Pseudo-ternary phase diagrams were prepared to identify the optimal surfactant mixture, with Tween 80 and Polyethylene Glycol 400 selected in a 2:1 ratio. A 23 factorial design was used to optimize formulation parameters, focusing on oil and surfactant mixture effects on globule size and viscosity.

RESULTS AND

CONCLUSIONS

The resulting microemulsions showed globule sizes between 60 ± 0.42 to 349 ± 0.13 nm, with optimal viscosity. In vitro release studies confirmed sustained drug release over 24 hours, following first-order kinetics. Skin permeation studies demonstrated enhanced drug penetration with SSZ-ME, while histopathological analysis revealed significant improvements in psoriatic symptoms in mice treated with 4% SSZ-ME compared to 2% SSZ-ME and marketed formulation. Blood analysis confirmed minimal systemic absorption and localized action. These results suggest that SSZ-ME offers a promising, patient-compliant, and effective topical therapy for psoriasis with improved therapeutic outcomes and minimal systemic exposure.