Development of an innovative essential-oil delivery system to counter sleep and appetite disorders.

Sleep and appetite disorders are highly prevalent conditions that significantly impact physical and psychological well-being. Their multifactorial etiology involves genetic, physiological, environmental, and behavioural factors, often coexisting with other medical or psychiatric conditions. Traditional pharmacological treatments, while effective, can produce side effects and may not be suitable for all patients, particularly those with comorbidities. In this context, essential oils represent a promising natural alternative. Among them, Citrus aurantium var. Dulcis aetheroleum essential oil has demonstrated the ability to act on the nervous system, improving both the quality and quantity of sleep through its relaxing and mild laxative effects. When administered via inhalation, it rapidly interacts with the limbic and hypothalamic regions, promoting relaxation, emotional balance, and overall homeostasis. Through similar mechanisms, sweet orange essential oil exerts its digestive and appetite-regulating properties. The aim of this thesis was to design a device simulating a pillow made of expanded polyurethane (EPU) foam loaded with chitosan nanoparticles encapsulating Citrus aurantium var. dulcis aetheroleum essential oil (EO-CS NPs), in order to achieve a controlled and sustained release of the active compound. EO-CS NPs were prepared using the ionic gelation technique, exhibiting a hydrodynamic diameter of 252 ± 27 nm as determined by Dynamic Light Scattering (DLS). The same analysis revealed a zeta potential of approximately +34 ± 2 mV, indicative of a stable nano-dispersion. Multimode plate reader was used to calculate a nanoparticle encapsulation efficiency of 84 ± 23 %. The release kinetics of the essential oil into the air were simulated using COMSOL Multiphysics software. The simulation was based on in vitro release data obtained at 20 °C and 37 °C. The EPU foam showed high porosity (82 ± 18 %) as observed by Scanning Electron Microscopy (SEM) and underwent plasma surface treatment to enable the binding of EO-CS NPs. The formation of this bond was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Finally, the cytocompatibility of the EO-CS NPs was evaluated through cytotoxicity and contact tests. This innovative system is intended to combine the comfort of a common household object with the therapeutic potential of aromatherapy, offering a practical and effective means to promote relaxation, improve sleep quality, and support appetite regulation through sustained essential oil diffusion.