Parkinson's disease: Current drug therapy and unraveling the prospects of nanoparticles

Parkinson's disease (PD), although being the second most prevalent neurodegenerative disease (ND) encounters lack of definitive treatment and challenges in drug delivery. There are enormous factors provoking degeneration of neurons in the substantia nigra of brain that leads to symptoms of Parkinson's, such as increase in oxidative stress, overexpression of α-synuclein, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) exposure, and many others. Among the current conventional marketed products used as anti-Parkinson drugs, levodopa is the absolute drug of choice, but is poor brain delivery and poor systemic bioavailability. Dopamine (DA) agonists, COMT inhibitor, anticholinergics, and MAO inhibitor are other drugs used in PD. But the side effects associated with these drugs were inevitable. To vanquish these drawbacks, nanoparticles (NP) drug delivery systems served as an excellent modality to provide maximum therapeutic efficacy of antiparkinson drugs. This review deliberates the incorporation of drugs used in PD in the nano-carriers, their ability to cross BBB, biodistribution of drug in brain and release profile of drug loaded NPs. NPs have also made it possible to administer the drug via different route of administration eliminating the requirement to pass BBB. The review is written with an objective to highlight the impact of nanoparticle drug delivery system in PD.