Formulation Development, Optimization and In vitro Characterization of Ursolic Acid and Boswellic Acid Based Nanoemulsion Drug Delivery System

Recent studies have demonstrated that phytoconstituents have the significant potential to treat inflammatory disorders of joints such as rheumatoid arthritis and osteoarthritis in an effective manner. The ursolic acid (UA) and boswellic acid (BA) are well-known phytochemicals for their remarkable anti-inflammatory and antiarthritic properties, but lipophilic nature of both UA and BA limits their solubility and therapeutic effectiveness. In the present study, an attempt has been made to develop an optimized and stable nanoemulsion of UA and BA to enhance their solubility. A Box-Behnken experimental design was employed to optimize the nanoemulsion formulation. The nanoemulsions were prepared using the high-speed homogenization method. In this study, the blend of castor oil and isopropyl myristate was used as oil phase, Tween 80 as surfactant, glycerol as co-surfactant, and distilled water used for formulation development. The optimized nanoemulsion formulation was evaluated for droplet size, transmittance, thermodynamic stability, drug content, and in vitro drug release. Additionally, in vitro anti-inflammatory activity of the optimized formulation was also evaluated by protein denaturation inhibition assay method. The results of study showed that optimized nanoemulsion had a droplet size of 123.845 nm, transmittance 97.85%, and drug content 94.01% respectively. Similarly, in vitro drug release studies exhibited 89.84% drug release in 5 hrs. The results of in vitro anti-inflammatory activity revealed significant anti-inflammatory effect in a dose-dependent manner compared to standard. In conclusion, the developed UA and BA loaded nanoemulsion exhibited high solubility, stability, significant drug release, and significant anti-inflammatory activity. Hence, it is logical to establish the concept that high-speed homogenization is a promising approach for the formulation of UA and BA loaded nanoemulsion with improved solubility and noticeable anti-inflammatory effects.