Encapsulating plant-based volatiles and their route of administration: A critical overview

Essential oils and their volatile constituents are complex mixtures of low molecular weight, lipophilic compounds characterized by high volatility, chemical instability, and limited aqueous solubility. Despite their well-documented biological activities, including antimicrobial, anti-inflammatory, antispasmodic and antioxidant effects, these physicochemical limitations significantly hinder their clinical and industrial applications. Nanocarrier-based delivery systems have emerged as promising strategies to overcome these challenges by enhancing stability, reducing volatility, improving solubility, and enabling controlled and targeted release. In recent years, a wide range of nanosystems, including lipid-based nanoparticles, polymeric carriers, and hybrid platforms, have been developed to optimize the delivery of volatile compounds across different administration routes. This review provides a critical and systematic analysis of nanoencapsulation strategies for volatile compounds, with a particular focus on the relationship between nanocarrier design and non-invasive administration routes (topical/transdermal, pulmonary, and oral). The influence of key physicochemical parameters, such as particle size, surface charge, and composition, on delivery efficiency and therapeutic outcomes is discussed. Furthermore, this work highlights how rational alignment between nanocarrier properties and route-specific biological barriers can enable more effective and “smarter” encapsulation strategies. Finally, current challenges, including formulation stability, potential toxicity, and scalability, are addressed, and future perspectives are proposed to guide the development of optimized nanodelivery systems for volatile compounds. This review provides a structured framework for the rational design of nanocarriers tailored to specific administration routes and therapeutic applications.