Novel Drug Delivery Systems for Releasing Growth Factors to the CNS: Focus on Alzheimer’s and Parkinson’s Diseases

Alzheimer’s disease (AD) and Parkinson’s disease (PD) represent the most common neurodegenerative disorders and affect more than 35 million people. Due to the limited effectiveness of available treatments in halting the neurodegenerative process, new therapies, such therapies based on growth factors (GFs), have been investigated. Nevertheless, the efficacies of these new treatments depend not only on the application of neurotrophins but also on the approaches used to deliver these proteins such that they can reach the brain. This review summarises the most widely used drug delivery systems (DDSs) for releasing GFs as possible treatments for AD and PD.