Safety, Stability Concerns, and Regulatory Aspects of Nanocarriers for Brain Delivery

Nanocarriers are nanosized materials used for targeted drug delivery purposes. The nanocarriers cross the blood–brain barrier by various mechanisms. The nanocarriers derived from metals, polymers, and other materials have shown their therapeutic efficacy against several neurological disorders during in vitro and preclinical studies. However, these nanocarriers, especially metal and silica NPs, have shown their toxicity against neuronal cell lines via the generation of reactive oxygen species, astrogliosis, and downregulation of glutathione. The discrepancies in the result may be due to their size, surface chemistry, and shape. The interaction between nanocarriers and living systems is not clear. These factors limit the safety and regulation of nanocarriers.