Nanostructured Lipid Carriers for Enhanced Delivery of Quercetin: A Comprehensive Review on Anti-Inflammatory Applications

Inflammation is a protective biological response; however, its persistence contributes to the progression of various chronic disorders. Conventional anti-inflammatory therapies provide symptomatic relief but are often associated with systemic side effects and limited therapeutic efficiency. This has led to growing interest in advanced drug delivery systems that can enhance efficacy while minimizing adverse effects. Natural bioactive compounds such as Quercetin exhibit potent anti-inflammatory and antioxidant properties, but their clinical application is restricted due to poor aqueous solubility, low bioavailability, and rapid metabolism. Nanostructured Lipid Carriers (NLCs), as second-generation lipid nanoparticles composed of a blend of solid and liquid lipids, have emerged as a promising approach to overcome these limitations. The imperfect lipid matrix of NLCs allows higher drug loading, improved stability, and controlled drug release. This review highlights the concept, design types, advantages, disadvantages, formulation methods, and evaluation parameters of NLCs, with a specific focus on quercetin-loaded systems. Furthermore, the incorporation of quercetin into NLC-based topical gels enhances skin penetration, retention, and sustained release, leading to improved therapeutic outcomes in inflammatory conditions. Overall, NLCs provide a versatile and efficient platform for the delivery of poorly soluble phytoconstituents. Future perspectives emphasize the need for optimization, large-scale production, and clinical validation to establish quercetin-loaded NLCs as a reliable and effective drug delivery strategy