Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: A Review of the Effect of Physicochemical Formulation Factors in the Optimization Process, Different Preparation Technique, Characterization, and Toxicity

Background:The high molecular weight and increasing lipophilicity drug face many problems starting from the drug development to formulation and conduction of pharmacological, toxicological and pharmacokinetic studies to its biological application. To overcome this problem, a different formulation of nano-sized drugs was developed recently. The use of Solid lipid nanoparticles (SLNs) and Nanostructured lipid carriers (NLCs) offers new insight into the formulation of the poorly soluble drug.Objective:The study aimed to investigate the literature with regard to the development of SLNs and NLCs for lipid-based nano drug delivery of poorly soluble drugs, with a view to identifying the factors influencing the optimization of the formulation of SLNs and NLCs and strategies to decrease the use of organic solvent during the preparation.Results:This review highlights the simple and easily scaled-up novel lipid nanoparticles (SLNs and NLCs) and their factors to be considered in the formulation for the proper selection of excipients. Also, this review summarizes the research findings reported by the different researchers regarding the principle formulation components, different preparation techniques, characterization, and toxicology of lipid nanoparticles.Conclusion:The SLNs/NLCs make this drug delivery system as one of the promising delivery systems, and safe colloidal lipid carriers for the delivery of poorly soluble drug and will be a solution to the formulation scientist for the solubility and permeability problem associated with the drugs to assure its good bioavailability.