Solid Lipid Nanoparticles and Nanostructured Lipid Particles: A 
Comparative Review on Lipid-Based Nanocarriers

Lipid-based nanocarriers have emerged as promising vehicles for the delivery of various therapeutic agents, owing to their biocompatibility, stability, and ability to encapsulate both hydrophilic and hydrophobic drugs. Among these lipid-based nanocarriers, Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs) have gained significant attention in the field of drug delivery. This comparative review aims to provide a comprehensive analysis of SLNs and NLCs, focusing on their formulation, physicochemical properties, drug-loading capacity, stability, and drug release profiles. The review highlights the differences in preparation techniques, particle size, zeta potential, drug encapsulation efficiency, stability, drug delivery, cosmetic and personal care, and food industry applications between SLN and NLC. Furthermore, the review discusses the toxicity and safety profiles of these nanoparticles, including cytotoxicity, genotoxicity, acute toxicity, and long-term toxicity. Finally, the review identifies the potential applications, limitations, and future research directions of SLN and NLC.In summary, this comparative review provides valuable insights into the formulation, physicochemical properties, drug-loading capacity, stability, and drug release profiles of SLNs and NLCs. By understanding the similarities and differences between these lipid-based nanocarriers, researchers and pharmaceutical scientists can make informed decisions regarding the selection of the most suitable nanocarrier for specific therapeutic applications.