Formulation development and optimization of nanoemulsion gel containing Prosopis cineraria, Aerva javanica, and Fagonia indica extracts for treatment of arthritis

Herbal extracts are interesting therapeutic candidates because they are enriched with numerous bioactive compounds which can be used to treat inflammatory disorders, such as rheumatic pain, inflammation, and arthritis. However, numerous issues are associated with the use of bioactive compounds, such as poor solubility, less permeability, confined bioavailability, and instability due to oxygen and light. In the present study, formulation and optimization of nanoemulsion containing Prosopis cineraria, Aerva javanica, and Fagonia indica hydroalcoholic extracts (0.2% w/w) was performed by the ultrasonication method. The response surface methodology was employed to optimize the nanoemulsion by using Box–Behnken experimental design. The oil concentration (oleic acid and olive oil), surfactant, and cosurfactant concentration (Tween 80 and soya lecithin) were three independent variables, and droplet size and % transmittance were two dependent variables. The droplet size, transmittance, polydispersity index, and zeta potential of optimized nanoemulsion formulation were 70.72 nm, 99.21%, 0.259, and −15.9 mV, respectively. The Fourier transform infrared analysis revealed that there was no interaction between the plant extracts and excipients. Hence, it can be concluded that these results will help in the design of nanoemulsion with optimum independent variables.