In vitro characterization of tofacitinib loaded novel nanoemulgel for topical delivery for the management of rheumatic arthritis

The purpose of the current study is to prepare the tofacitinib (TFB) nanoemulgel (NEG) for topical administration with optimized particle size, high loading efficiency, and better penetration through the skin for the treatment of rheumatic arthritis. The topical delivery of this drug avoids the hazards associated with oral delivery like upper respiratory tract infections and neutropenia. The formulations were prepared using the high-energy ultrasonication method. Oleic acid, tween 80, and propylene glycol were used to prepare TFB nanoemulsion (NE) which is then homogenized with carbopol-934 hydrogel to get the NEG loaded with TFB. The concentration of independent variables such as X₁ (oil phase), X₂ (surfactant), and X₃ (cosurfactant) was optimized using the Box-Behnken design to check its impact on dependent variables such as Y₁ (particle size) and Y₂ (loading efficiency) of the NE. The minimum particle size of 106.3 ± 2.8 nm and maximum loading efficiency of 19.3 ± 1.8% were obtained for NE. The NEGs were evaluated for different organoleptic and physicochemical stability which were found within the normal range. The in vitro release studies showed 89.64 ± 0.97% cumulative release of TFB from NEG over the period of 24 h. The drug release data were fitted in different kinetic models and it followed Higuchi and Korsmeyer-Peppas model clearly showing the non-Fickian drug release from matrix system. As a result, the TFB NEG that have been produced could be a viable delivery mechanism for topical route.