Formulation evaluation of ketoconazole microemulsion‐loaded hydrogel with nigella oil as a penetration enhancer

BACKGROUND: Onychomycosis is an opportunistic fungal infection often infecting people with compromised immune system. Currently available treatment interventions such as physical, surgical, and chemical-based approaches are successful in treating the condition, however, are painful and nonpatient complaint. Moreover, dermal creams with antifungal agents do not penetrate nail plate as required; hence, there is a necessity of developing a novel formulation with enhanced penetration. AIMS: The aim of the present research work was to develop ketoconazole microemulsion-loaded hydrogel formulation containing nigella oil as permeation enhancer for the treatment of onychomycosis. METHODS: Screening of oils, surfactants, and cosurfactants were done based on solubility studies followed by the construction of pseudo-ternary phase diagrams with 2% ketoconazole. The microemulsion was characterized for globule size, zeta potential, viscosity, and thermodynamic stability. Ex-vivo studies were carried out using Franz diffusion cells using porcine skin membrane. The antifungal activity of microemulsion-loaded hydrogel was evaluated using cup plate method using Candida albicans and Aspergillus niger. RESULTS: The optimized microemulsion had a composition of 54.97% Capryol:Nigella (2:1), 36.07% Transcutol:Propylene glycol (2:1), and 7.13% water and was later incorporated into polymeric gel base. The microemulsion-loaded hydrogel exhibited a 10 hours sustained release profile as compared to the marketed cream and an enhanced activity against marketed ketoconazole cream and compared with marketed ketoconazole formulation. CONCLUSION: The thermodynamic stability, sustained drug release with greater permeation, and enhanced activity due to the presence of nigella oil in microemulsion-loaded hydrogel warrant its application as an excellent vehicle for treating fungal infections.