The blood–brain barrier (BBB) serves as a protective barrier for the central nervous system (CNS) against drugs that enter the bloodstream. The BBB is a key clinical barrier in the treatment of CNS illnesses because it restricts drug entry into the brain. To bypass this barrier and release relevant drugs into the brain matrix, nanotechnology-based delivery systems have been developed. Given the unstable nature of NPs, an appropriate amount of a biocompatible polymer coating on NPs is thought to have a key role in reducing cellular cytotoxicity while also boosting stability. Human serum albumin (HSA), poly (lactic-co-glycolic acid) (PLGA), Polylactide (PLA), poly (alkyl cyanoacrylate) (PACA), gelatin, and chitosan are only a few of the significant polymers mentioned. In this review article, we categorized polymer-coated nanoparticles from basic to complex drug delivery systems and discussed their application as novel drug carriers to the brain.
