Salicylic Acid Emulgel: Design, Development, and Assessment for Psoriasis Treatment

Aims and Objectives: The present research aimed to develop and optimize a salicylic acid–tea tree oil emulgel for the topical management of psoriasis, with enhanced therapeutic efficacy and patient compliance. Background: Psoriasis is a long-term autoimmune skin condition marked by inflammation and hyperproliferation of keratinocytes. results: Salicylic acid emulgel using suitable excipients was formulated for the management of psoriasis. The oil used was tea tree oil and the drug was dissolved in oil with gentle mixing forming the oil phase of emulsion. The aqueous phase consists of water, surfactant and co surfactant. Tween 80 and methanol were used at concentration and were continuously stirred on magnetic stirrer for 1 hour at 300rpm when tween 80 was totally dissolved in water. The aqueous phase was added to the oil phase with continuous stirring. Total volume of emulsion was 10ml. The maximum drug release from emulgel was found to be 90.950% from the batch F14. Methods: The formulation combined the keratolytic activity of salicylic acid with the anti- inflammatory and antimicrobial effects of tea tree oil to achieve synergistic therapeutic action. Optimization was performed using a Box–Behnken Design (DoE), selecting oil concentration, surfactant to co-surfactant ratio, and water content as key variables. discussion: The Korsmeyer-Peppas model had the highest R2 (0.971) value for the in vitro release data for F14 out of all the models, followed by the Higuchi model (0.911). In the current study, the values of n in the Korsmeyer-Peppas model for in vitro release data in Phosphate Buffer (pH 7.4) were found to be 0.539, indicating that non-fickian anomalous diffusion is the release mechanism followed by the salicylic acid loaded emulgel. Results: The optimized emulgel (F15) exhibited a droplet size of 225 nm, a stability index of 92%, and an entrapment efficiency of 96.28%. Rheological analysis confirmed suitable viscosity (4765 cP) and 35.72 spreadability for topical use. The optimized formulation demonstrated maximum drug release of 86.36 % within 12 h, following the Korsmeyer–Peppas kinetic model (R² = 0.952), indicating a non-Fickian diffusion mechanism. Conclusion: The developed emulgel thus provides an effective and patient-friendly alternative for psoriasis management, combining enhanced diffusion-controlled drug release with the natural therapeutic benefits of tea tree oil. Future work will include ex vivo skin permeation and in vivo evaluation to confirm clinical translation.