Stability study of clobetasol propionate loaded tea tree oil nanoemulsion as per ICH guidelines

The nanoemulsion formulation containing clobetasol propionate (CP) was prepared by spontaneous emulsification method. For the formulation of nanoemulsion Tea tree oil, Tween 80, transcutol P, and distilled water were used. Drug was incorporated in oil phase in 0.05% w/v. The lipohilic nature of drug leads to O/W nanoemulsion formulation. These were characterized by droplet size, pH, viscosity, conductivity and refractive index. Stability studies were performed as per ICH guideline for a period of 3-months. Shelf-life of nanoemulsion formulation was also determined after performing the accelerated stability testing. It was found that the droplet size, conductivity and refractive index were slightly increased while viscosity and pH, slightly decreased at refrigerator (4ºC), room temperature (25ºC) and 40°C during 3 months of storage period. However, the changes in these parameters were not statistically significant (p≥0.05). The degradation (%) of optimized nanoemulsion of CP were determined and the shelf-life was found to be 13.28 months at room temperature. These results indicated that the physical and chemical stability of CP were maintained in nanoemulsion formulation.