Nanoparticle Formulations for the Improvement of Symptomatic Treatments of Neurodegenerative Disorders

Neuronanomedicine merges nanotechnology and neuroscience in the pursuit of engineering therapeutic interventions for neurological disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD). While no nanoparticle-based drug delivery systems (NDDSs) are yet approved for use for targeting the central nervous system, this review critically analyses the development of NDDSs for the improvement of currently approved therapeutics for the symptomatic treatment of AD and PD. It showcases how NDDSs can help therapeutic payloads overcome existing limitations, such as insufficient drug accumulation in the brain and limited effectiveness, by enhancing their pharmacokinetics, bioavailability, brain penetration and accumulation, and overall therapeutic efficacy through drug encapsulation, manipulation of nanoparticle properties, and nanoparticle surface functionalisation. However, we also draw attention to widespread issues in the field that impede progress, including the poor selection of in vitro models and the inadequate design of pre-clinical in vivo studies. We further advocate for greater standardisation of study design and reporting requirements in the future, which would likely enhance outcomes and expedite the translation of neuronanomedicines.