Nanoemulsion-based hydrogels containing Aniba canelilla (H.B.K.) Mez essential oil for topical use: in vivo anti-inflammatory efficacy

Aniba canelilla (H.B.K.) Mez essential oil contains 1-nitro-2-phenylethane (NP) and methyleugenol (ME) as main compounds. Despite traditional medicine practices and scientifically proven anti-inflammatory activity1-3, there are no reports of development of a semisolid pharmaceutical form containing A. canelilla essential oil to the treatment of topical inflammation. Hydroxyethylcellulose and chitosan hydrogels-thickened nanoemulsion containing A. canelilla essential oil (HNE and CNE) were developed to increase the viscosity, adhesion and stability of nanoemulsion, beyond favoring topical therapy. Both hydrogels exhibited adequate stability with low droplet size, pseudoplastic behavior, bioadhesive characteristics, controlled release profile, and were able to deliver NP and ME to the dermis, the target site concerning topical inflammation. HNE appeared to be a promising formulation as it presented a low irritant potential in HET-CAM test and a promising anti-inflammatory response, decreasing edema, lowering polymorphonuclear leukocytes migration and reducing synthesis/release of inflammatory mediators primarily attributed to the essential oil compounds.