A Review of the Potential Role of Nano-Enabled Drug Delivery Technologies in Amyotrophic Lateral Sclerosis: Lessons Learned from Other Neurodegenerative Disorders

Amyotrophic lateral sclerosis (ALS) has a multitude of factors implicated in its etiology. The complex neuro-etiology and the restrictive nature of the blood-brain barrier (BBB) have significantly hindered the drug therapy of ALS. Riluzole, a moderately performing drug, is the only agent approved for treating ALS. However, several promising nanocarrier approaches are surfacing that can provide more efficient drug delivery. In addition, biologicals such as stem cells are able to carry neurotrophic factors to their target site, providing motor neurons with the benefits of both, stem cells and neurotrophic factors. This review examines the current drug delivery strategies investigated for optimally treating ALS and related neurodegenerative disorders. Examples include cerium oxide nanoparticles in Alzheimer's disease, odorranalectin, and lactoferrin-coupled PEG-PLGA nanoparticles for urocortin transportation in Parkinson's disease that can also be employed in ALS to bypass the BBB and increase drug bioavailability. A concise incursion into the progress (and lack thereof) made in ALS clinical trials is also discussed. Nanocarriers can potentially eliminate the challenges of poor drug bioavailability in ALS as they have been proven to cross the BBB and reach target sites while minimizing systemic side-effects. Nanocarrier-based delivery of ALS drugs is an area that requires much needed investigation.