Recent developments in quercetin nanomedicine and applications in osteoarthritis and rheumatoid arthritis therapies.

Quercetin has attracted increasing attention in the research of treatments for rheumatoid arthritis and osteoarthritis due to its excellent anti-inflammatory, antioxidant, and joint-protective effects. However, the bioavailability of quercetin is relatively low, primarily due to its poor solubility, rapid metabolism, and high clearance rate. Nanotechnology offers new opportunities to enhance the bioavailability of quercetin. Nanoformulations possess many advantages, such as a larger surface area, which can effectively improve the solubility of quercetin. Encapsulating quercetin in nanocarriers can prolong its residence time in the body, thereby improving its bioavailability and therapeutic efficacy. Targeted delivery can be achieved by modifying the surface of nanocarriers with ligands, allowing for direct transport of the drug to the site of injury and increasing the concentration at the lesion site. Nanocarriers can improve drug targeting and release behavior by adjusting their surface properties, thereby enhancing therapeutic effects. This article first summarizes the general preparation methods, drug-loading approaches, and common nanoformulations for quercetin. It then lists and summarizes the applications of quercetin nanoparticle formulations in rheumatoid arthritis and osteoarthritis. Finally, it concludes with a summary and outlook on the clinical applications and challenges associated with quercetin nanoformulations.