Optimization of clobetasol propionate loaded niosomal gel for the treatment of psoriasis: Ex vivo and efficacy study

Abstract

Psoriasis is a chronic autoimmune inflammatory skin disease treated using corticosteroids. The current topical therapy is very challenging owing to the physicochemical nature of corticosteroids and thick psoriatic stratum corneum. In this paper, clobetasol propionate-loaded niosomal gel was tailored to increase drug permeation and deposition (high local drug concentration) in the psoriatic area for effective management of psoriasis. Thin film hydration technique and sonication was used to formulate niosomal gel using Span 60, cholesterol 934 (as gelling agent). Size (188 nm) and entrapment efficacy (78%) of the niosomes were optimized using Box Behnken design (BBD) approach by selecting cholesterol = 261.6 mg, Span 60 = 1.49% and sonication time = 8.6 min. The optimized niosomal gel showed acceptable size (188 ± 6 nm), zeta potential (−38 ± 6 mV), and viscosity (8521 ± 121 cp) for topical application. The ex vivo permeation profile showed high permeability of niosomes (61.12 ± 1.89% in 24 h) compared to marketed clobetasol propionate cream USP (8.56 ± 2.5% in 24 h). Niosomal gel showed 5.1-fold improvement in drug deposition in stratum corneum and viable layers compared to marketed cream. Fluorescence study indicates high localization of vesicular system in the skin layers. Further, in imiquimod-induced psoriatic model, the PASI (psoriasis area severity index) was significantly decline (better efficacy) with gel compared to marketed cream. Thus, the data demonstrated the potential of niosomal gel to improve drug permeation and deposition in the affected skin for effective management of psoriasis.