Challenges and Opportunities of Deferoxamine Delivery for Treatment of Alzheimer's Disease, Parkinson's Disease, and Intracerebral Hemorrhage.

Deferoxamine mesylate (DFO) is an FDA-approved, hexadentate iron chelator routinely used to alleviate systemic iron burden in thalassemia major and sickle cell patients. Iron accumulation in these disease states results from the repeated blood transfusions required to manage these conditions. More recently, iron accumulation has been implicated in the pathogenesis of Alzheimer's Disease (AD), Parkinson's Disease (PD), and secondary injury following Intracerebral Hemorrhage (ICH). Chelation of brain iron is thus a promising therapeutic strategy for improving behavioral outcome and slowing neurodegeneration in the aforementioned disease states, though the effectiveness of DFO treatment is limited on several accounts. Systemically administered DFO results in non-specific toxicity at high doses, and the drug's short half-life leads to low patient compliance. Mixed reports of DFO's ability to cross the Blood-Brain Barrier (BBB) also appear in literature. These limitations necessitate novel DFO formulations prior to the drug's widespread use in managing neurodegeneration. Herein, we discuss the various dosing regimens and formulations employed in intranasal or systemic DFO treatment, as well as the physiological and behavioral outcomes observed in animal models of AD, PD, and ICH. The clinical progress of chelation therapy in managing neurodegeneration is also evaluated. Finally, the elimination of intranasally administered particles via the glymphatic system and efflux transporters is discussed. Abundant preclinical evidence suggests that intranasal DFO treatment improves memory retention and behavioral outcome in rodent models of AD, PD, and ICH. Several other biochemical and physiological metrics such as tau phosphorylation, survival of tyrosine hydroxylase-positive neurons, and infarct volume, are also positively affected by intranasal DFO treatment. However, dosing regimens are inconsistent across studies and little is known about brain DFO concentration following treatment. Systemic DFO treatment yields similar results, and some complex formulations have been developed to improve permeability across the BBB. However, despite the success in preclinical models, clinical translation is limited with most clinical evidence investigating DFO treatment in ICH patients, where high-dose treatment has proven dangerous and dosing regimens are not consistent across studies. DFO is a strong drug candidate for managing neurodegeneration in the aging population, but before it can be routinely implemented as a therapeutic agent, dosing regimens must be standardized and brain DFO content following drug administration must be understood and controlled via novel formulations.