Development of Micro-Emulsion Gel Based Topical Delivery of Salicylic Acid and Neem Oil for the Management of Psoriasis

Microemulsions (MEs) are clear, thermodynamically stable systems. They were used to solubilise drugs and to improve topical drug availability. Salicylic acid (SA) is a keratolytic agent used in topical products with antimicrobial actions. This study aimed to formulate an optimized SA micro emulsion gel for the slow, variable and incomplete oral drug absorption in patient suffering from psoriasis infection. The dispersion solubility of SA was studied in various oils, surfactants and co-surfactants and by constructing pseudo phase ternary diagram, micro emulsion area was identified. The optimized formulations of micro emulsion were subjected to thermodynamic stability tests. After stability study, stable formulation was characterized for droplet size, pH determination, centrifugation, % drug content in micro emulsion, zeta Potential and vesicle size measurement and then micro emulsion gel were prepared and characterized for spreadability, measurement of viscosity, drug content, In-vitro diffusion, in-vitro release data. Labrasol was selected as surfactant, plurol oleique as co surfactant and neem oil as oil component based on solubility study. The optimized formulation contained SA 0.05 (%w/w), labrasol (24%), plurol oleique (8 %) and neem oil (8%). The in vitro drug release from SA micro emulsion gel was found to be considerably higher in comparison to that of the pure drug. The in-vitro diffusion of micro emulsion gel was significantly good. Based on this study, it can be concluded the solubility and permeability of SA can be increased by formulating into micro emulsion gel. Keywords: Salicylic Acid, Neem Oil, Micro-emulsion, In-vitro diffusion, Zeta potential, Stability, Labrasol