Physicochemical properties and antioxidant activity of polyvinyl alcohol orally disintegrating films containing sweet almond oil nanoemulsion

This study aimed to extract sweet almond oil (SAO), prepare and characterize its nanoemulsion, produce polyvinyl alcohol (PVA) orally disintegrating films (ODFs) containing 20% and 40% of SAO nanoemulsion and characterize the in vitro disintegration time, color parameters, mechanical, structural, morphological and thermal properties, water contact angle and antioxidant activity stability of ODFs. Dynamic light scattering (DLS) confirmed the formation of a nanoemulsion with droplet size, polydispersity index, and zeta potential of 81.7 nm, 0.28 and, + 13.5 mV, respectively. The formation of new hydrogen bonds between PVA chains and SAO nanoemulsion droplets was revealed by ATR-FTIR spectroscopy. Due to XRD results, the crystallinity of the ODFs was increased by SAO nanoemulsion addition. According to FE-SEM images, when SAO nanoemulsion concentration increased, the aggregation of nanoemulsion droplets was observed. The ODF containing 20% nanoemulsion had the highest thermal stability in TGA. Moisture absorption and moisture content of the ODF samples decreased by SAO nanoemulsion addition. All films had excellent color parameters with very little opacity. Although the incorporation of SAO nanoemulsion led to a high hydrophobicity and water contact angle but increased disintegration time values are in the standard accepted range. The SAO nanoemulsion containing ODFs were very efficient in maintaining antioxidant activity as a function of the storage time and temperature. Overall, the results shows that the PVA films containing SAO nanoemulsion can be used as an effective ODF with high antioxidant potential.