Antioxidant Delivery Revisited: The Promise of Nanostructured Lipid Carriers

Natural products have an invaluable therapeutic effect on human health. Natural antioxidants, including beta-carotene, turmeric, and polyphenols, are recognised for their health benefits but face significant barriers related to insufficient solubility, instability, volatility, and diminished bioavailability, which limit their therapeutic efficacy in drug delivery systems. Therefore, encapsulation of natural products in a carrier addresses the above concern. Drug delivery systems, such as solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), are promising carriers for effective release, consisting of solid and liquid lipids, which enhance efficiency, stability, and controlled release, thereby minimising bioavailability limitations. This review consolidates current studies on the formulation methodologies, mechanisms of action, and therapeutic applications of NLCs, emphasizing their use in the treatment of conditions such as cancer, neurological disorders, and cardiovascular diseases. The results demonstrate that NLCs substantially enhance the bioavailability and therapeutic efficacy of antioxidants, thereby improving their targeted administration and clinical effects. Nonetheless, difficulties in clinical translation remain, including drug loading capacity, regulatory authorisation, and the need for pervasive research on cytotoxicity. This article highlights important areas for future inquiry, specifically the optimisation of NLC formulations, the enhancement of targeting accuracy, and the resolution of safety issues to enhance their clinical application.