Development of ketorolac tromethamine loaded microemulsion for topical delivery using D-optimal experimental approach: Characterization and evaluation of analgesic and anti-inflammatory efficacy

Abstract

Aim of the present study was to evaluate the potential of microemulsions for the transdermal delivery of ketorolac tromethamine. The pseudo ternary phase diagram, 3 D Optimal mixture design was used to develop the microemulsion of desired properties. Seventeen trial runs were executed by using three different variables, percent content of oil, water and the optimized ratio of surfactant and co-surfactant whereas the responses investigated were percentage transmittance and Globule size. This microemulsion system was composed of, eucalyptus oil, Methyl Salicylate, tween 80, labrafil 1944 M, and butanol. The optimized microemulsion was characterized by pH, Zeta Potential, Globule size, Polydispersity Index, and Viscosity. The surface morphology of microemulsion globules was performed by Transmission Electron Microscopy (TEM). Ex-vivo permeation study and in-vitro drug release study (flux, Permeability coefficient, and Enhancement ratio (Er)) was also performed by using excised goat skin in a modified Franz diffusion cell. The stability study of the formulations was performed at three different temperature conditions for 90 days to prove the stability of the formulation. Optimized MEK-1 formulation was assessed for its anti-inflammatory activity by Croton oil-induced ear edema test and Croton oil-induced capillary permeability. Additionally, analgesic activity was also performed by Formalin Test and Heffner's tail clip method. The study concluded that optimized microemulsion has potential and can be used as an alternative tool for the delivery of ketorolac tromethamine via the transdermal route.