Functionalized biomaterials based on poly(vinyl alcohol) and chitosan as a vehicle for controlled release of cabreuva essential oil

Abstract

The poly(vinyl alcohol) (PVA), a biodegradable and semicrystalline polymer composed of vinyl monomer ?(CH2?CHOH)n− units, combines different advantages such as biodegradability, good mechanical, and adhesive properties, among others. The essential oils (EOs) are volatile secondary metabolites of plants, and consist of terpenes and sesquiterpenes of low water solubility; therefore, encapsulation through the formation of micro and nanoemulsions is an effective approach to overcome this drawback. The formulation of PVA-based nanocomposites loaded with emulsions of chitosan and cabreuva essential oil (Myrocarpus fastigiatus) was proposed. Nanocomposites were prepared by varying the PVA:emulsion ratio (PVA:Em3:2, 1:1, and 2:3) using 0.125% w/v sodium citrate as a cross-linking agent. The presence of emulsions produced microstructural changes at the crystallinity level, an effect that was observed more clearly in the sample with the highest emulsion content and was supported by DSC, XRD, and ATR-FTIR. Also, the influence of chitosan in the nanocomposite PVA:Em was studied by XRD, DSC, DMA, and TGA. The controlled release profile of the PVA:Em 1:1 nanocomposite in media with equivalent quantities of PBS and ethanol led to the highest release of the active compound, fitting the experimental data satisfactorily with the Gallagher and Corrigan model.