Essential Oil-Loaded Lipid Nanocarriers with Anti-Inflammatory Activity: Quality Control, Safety, and Efficacy

Inflammation is a complex biological response involved in the pathophysiology of several chronic diseases. Although conventional anti-inflammatory therapies are effective, their prolonged use can be associated with relevant adverse effects. Although non-steroidal anti-inflammatory drugs and glucocorticoids are widely used, these agents cause gastrointestinal, renal, cardiovascular, hepatic and metabolic adverse effects. Essential oils (EO) exhibit relevant anti-inflammatory potential. However, their pharmaceutical application is limited by volatility, hydrophobicity, physicochemical instability and potentially low bioavailability. This review evaluated EO-loaded lipid nanocarriers for anti-inflammatory applications, with emphasis on physicochemical quality attributes, stability, safety and efficacy. Literature searches were carried out through PubMed/MEDLINE, PubMed Central, ScienceDirect, SciELO, Virtual Health Library, and Google Scholar websites, based on works published between 2021 and 2026. The investigated systems included liposomes, solid lipid nanoparticles, nanostructured lipid carriers and nanoemulsions. Different formulations were found regarding EO nature, nanocarrier type, administration route and biological models used, predominantly involving preclinical assays. Nanoencapsulation was frequently associated with suitable physicochemical properties and release profiles, but direct comparisons with the corresponding free EO and control nanocarriers were not consistently performed. Safety findings were mainly based on cytotoxicity, local tolerability and short-term assays, with limited repeated-dose and long-term toxicological data. Several formulations showed anti-inflammatory activity in acute, subacute, or chronic experimental models. In selected works using the same experimental conditions, some formulations produced responses of similar magnitude to hydrocortisone, diclofenac, or other anti-inflammatory drugs, but these results cannot be directly correlated with therapeutic equivalence. The reported mechanisms involved modulation of the NF-κB, MAPK and Keap1/Nrf2/HO-1 signaling pathways. Overall, lipid-based nanocarriers represent platforms for investigating the stability, delivery and biological performance of EO. However, further standardization and controlled assays are required to determine their therapeutic and translational potential.