Efficiency of lipid-based nano drug delivery systems in crossing the blood–brain barrier: A review

•Lipid-based drug delivery systems are highly efficient in crossing the BBB.•Receptor and clathrin mediated transcytosis are the most important mechanisms for crossing the BBB.•Size, shape, surface charge and surface modification of nanoparticles are effective in crossing the BBB. The blood–brain barrier (BBB) is one of the vital and key barriers between brain tissue and the circulatory system. The BBB controls the passage of ions and molecules into brain tissue. Due to the unique features of this barrier, drug delivery for the treatment of various brain disorders is still a major challenge in the medical field. The use of nanoparticle formulations that have the ability to encapsulate molecules for therapeutic purposes may improve the passage of drugs through the BBB. In the meantime, due to the lipid nature of the BBB endothelial cell membrane, the use of lipid-based drug delivery systems may be preferable to other drug nanocarriers. In this review, we briefly discuss the physiology of the BBB as well as the efficacy of various nanoparticles in delivering drugs to the brain. In addition, the advantages and applications of lipid-based drug delivery systems (solid lipid nanoparticles, liposomes, niosomes, and nanostructured lipid carriers) in crossing the BBB are discussed. In addition, various mechanisms of lipid nanoparticles as well as effective factors for the passage of these nanoparticles through the BBB have also been discussed.