Physicochemical properties of rosemary essential oil-based nanoemulsions and their implications for oral health: proof-of-concept in vitro studies

This study aimed to develop and characterize a stable rosemary essential oil (REO) nanoemulsion for intraoral use utilizing a low-energy spontaneous emulsification method and to assess its potential in oral healthcare. REO was obtained via hydrodistillation and characterized by GC-MS. Nanoemulsions were prepared using different concentrations of REO and polysorbate 20, followed by physicochemical stability, droplet size, and zeta potential analyses. Bioadhesion and biorheological properties were evaluated by contact angle measurements and rheological testing using artificial saliva. The formulated nanoemulsions displayed excellent stability, desirable droplet sizes, and zeta potential values, indicating their potential for effective delivery within the oral cavity. The antioxidant capacity of REO was confirmed by DPPH assays. The nanoemulsions exhibited favorable bioadhesion properties and altered the rheological behavior of saliva mixtures in a concentration-dependent manner. This study successfully formulated stable REO nanoemulsions with antioxidant and bioadhesive properties, making them promising candidates for use in oral healthcare products.