Objective: The aim of the present study was to investigate the skin penetration potential of emu oil and the possibility of enhancing the antiarthritic potential of lipophilic bioactive curcumin, which has poor permeability through biological membranes.
Methods: Solubility and ex vivo skin permeation studies were performed with water, corn oil, and emu oil as a vehicle using curcumin as a model drug. Carrageenan induced inflammation and Freund's complete adjuvant-induced arthritic rat models were used to evaluate enhanced antiinflammatory and antiarthritic effect of curcumin in combination of emu oil via topical route.
Results: The skin permeation study resulted in the combination of emu oil with curcumin enhancing the flux 1.84 and 4.25 times through the rat skin compared to corn oil and water, respectively. Results of carrageenan induced rat paw edema model demonstrated that percentage of paw inhibition shown by curcumin-emu oil combination was 1.42-fold more compared to the total effect shown by both groups treated with curcumin aqueous suspension and emu oil per se. In Freund's complete adjuvant-induced arthritic model, the combined treatment was effective in bringing significant changes in the functional, biochemical, histopathologic, and radiologic parameters. Topical application of curcumin-emu oil combination resulted in significant reduced levels of proinflammatory mediators TNF-α, IL-1 β, and IL-6 (P < 0.05, 0.001, and 0.01, respectively) compared to arthritic animals.
Conclusion: Topical delivery of curcumin with emu oil holds promise as a noninvasive and efficacious intervention for the treatment of inflammatory arthritis and it assists in further development of a topical formulation of curcumin using emu oil as a vehicle.
Keywords: Adjuvant induced arthritis; Curcumin; Cytokines; Emu oil; Inflammation; Topical application.
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