Nanoemulsions as Carriers for Natural Antioxidants: Formulation Development and Optimisation

In the era of returning to the compounds derived from natural sources, antioxidants and other botanical bioactive molecules are gaining increased popularity. Due to their proven health benefits, they have been extensively explored in pharmaceutical, food and cosmetic fields. In addition to their key roles in disease prevention and treatment, cosmetic care and food supplementation, these versatile molecules play a significant role in the development of innovative packaging materials. However, the application of natural antioxidants is still limited due to their inherent sensitivity to environmental conditions. The use of nanoemulsions as suitable carriers for natural antioxidants presents a promising approach to overcoming their stability issues and improving their biological performance. This chapter aims to comprehensively cover recent and relevant findings regarding the formulation design of nanoemulsions (selection of oils and stabilisers, and their ratio) and their preparation methods (high- and low-energy processes). In addition, it provides useful methodological information on the characterisation procedures for the antioxidant-loaded nanoemulsions (antioxidant activity assessment, in vitro biological safety and efficacy evaluation). Aiming to guide researchers towards successful formulation development and reliable assessment protocols for these promising colloidal systems, this chapter combines established theoretical concepts with recent experimental results, alongside the most relevant literature sources.