A chitosan hydrogel-thickened nanoemulsion containing Pelargonium graveolens essential oil for treatment of vaginal candidiasis

The use of nanosystems can be an appropriate approach to develop essential oils formulations by improving their active compounds delivery. This work reports an evaluation of antifungal activity of essential oils of Pelargonium graveolens from different countries and the development of a mucoadhesive hydrogel-thickened nanoemulsion containing the essential oil to treat vaginal candidiasis. The antifungal activities of six essential oils were evaluated against five species of Candida. Then, a hydrogel-thickened nanoemulsion with the most active essential oil was produced, characterized and had its MIC determined. Formulations were also monitored for irritancy properties by HET-CAM test and had their mucoadhesive properties assessed. The hydrogel containing the essential oil of P. graveolens showed higher antifungal activity reaching MIC values 64 times lower when compared to essential oil dilution and to nanoemulsion. Also, the final formulation showed droplets lower than 300 nm with positive zeta potential, reduced irritant potential and better mucoadhesive properties when compared to the nanoemulsion. Thus, it can be considered a promising alternative to treat vaginal candidiasis, once it showed an improvement in antifungal activity against Candida spp., besides having biodegradable materials and mucoadhesive properties, increasing the time residence on vaginal mucosa, leading to an improvement of treatment efficacy.