Solid lipid nanoparticles as a drug delivery system for the treatment of neurodegenerative diseases

<b>Introduction</b>: The failure of many molecules as CNS bioactive compounds is due to many restrictions: poor water solubility, intestinal absorption, <i>in vivo</i> stability, bioavailability, therapeutic effectiveness, side effects, plasma fluctuations, and difficulty crossing physiological barriers, like the brain blood barrier (BBB), to deliver the drug directly to the site of action. <b>Area covered</b>: Nanotechnology-based approaches with the employment of liposomes, micelles, dendrimers, and solid lipid nanoparticles (SLN) as drug delivery systems, are used to overcome the above reported limitations. Here, we focus on the delivery of drugs based on SLN formulation to treat neurodegenerative diseases. Notably, SLN have the ability to protect drugs from chemical and enzymatic degradation, direct the active compound towards the target site with a substantial reduction of toxicity for the adjacent tissues, and pass physiological barriers increasing bioavailability without resorting to high dosage forms. <b>Expert opinion</b>: We believe that SLN could represent a suitable tool to pass the BBB and permit drugs to reach damaged areas of the CNS in patients affected by neurodegenerative pathologies, such as Alzheimer’s and Parkinson’s diseases.