Enhancement of skin permeation and anti-inflammatory effect of indomethacin using microemulsion

The objective of the present study was to investigate the potential of microemulsion formulations for transdermal delivery of indomethacin (IND). Microemulsion formulations with different surfactant: cosurfactant ratios (S-mix); F1-F6 (1:1, 2:2, 3:1, 4:1, 1:2, and 3:2) were prepared by the spontaneous emulsification method, and characterized for morphology, droplet size, and rheological characteristics. The ex vivo skin permeation studies were performed using Franz diffusion cell with rabbit skin as a permeation membrane. A significant increase in the steady-state flux (J(ss)), permeability coefficient (K-p), and enhancement ratio (E-r) was observed in microemulsion formulations compared with the conventional IND gel. The antiinflammatory effects of microemulsion formulations showed a significant increase in percent edema inhibition value after 4 hours. The optimized formulation showed a significant increase in the steady-state flux (J(ss)) and permeability coefficient (K-p). The enhancement ratio (E-r) was found to be 8.939 in optimized formulation F1 compared with IND gel.