Mechanism-Based Pharmacokinetic Modeling of Absorption and Disposition of a Deferoxamine-Based Nanochelator in Rats

Developing Iron Nanochelating Agents: Preliminary Investigation of Effectiveness and Safety for Central Nervous System Applications

Excessive iron levels are believed to contribute to the development of neurodegenerative disorders by promoting oxidative stress and harmful protein clustering. Novel chelation treatments that can effectively remove excess iron while minimizing negative effects on the nervous system are being explored. This study focuses on the creation and evaluation of innovative nanobubble (NB) formulations, shelled with various polymers such as glycol-chitosan (GC) and glycol-chitosan conjugated with deferoxamine (DFO), to enhance their ability to bind iron. Various methods were used to evaluate their physical and chemical properties, chelation capacity in diverse iron solutions and impact on reactive oxygen species (ROS). Notably, the GC-DFO NBs demonstrated the ability to decrease amyloid-β protein misfolding caused by iron. To assess potential toxicity, in vitro cytotoxicity testing was conducted using organotypic brain cultures from the substantia nigra, revealing no adverse effects at appropriate concentrations. Additionally, the impact of NBs on spontaneous electrical signaling in hippocampal neurons was examined. Our findings suggest a novel nanochelation approach utilizing DFO-conjugated NBs for the removal of excess iron in cerebral regions, potentially preventing neurotoxic effects.

Application of Allometric Scaling to Nanochelator Pharmacokinetics

Deferoxamine (DFO) is an effective FDA-approved iron chelator; however, its use is considerably limited by off-target toxicities and an extremely cumbersome dose regimen involving daily infusions. The recent development of a deferoxamine-based nanochelator (DFO-NP) with selective renal excretion has shown promise in ameliorating iron overload and associated physiological complications in rodent models with a substantially improved safety profile. While the dose- and administration route-dependent pharmacokinetics (PK) of DFO-NPs have been recently characterized, the optimized PK model was not validated, and the prior studies did not directly address the clinical translatability of DFO-NPs into humans. In the present work, these gaps were addressed by applying allometric scaling of DFO-NP PK in rats to predict those in mice and humans. First, this approach predicted serum concentration-time profiles of DFO-NPs, which were similar to those experimentally measured in mice, validating the nonlinear disposition and absorption models for DFO-NPs across the species. Subsequently, we explored the utility of allometric scaling by predicting the PK profile of DFO-NPs in humans under clinically relevant dosing schemes. These in silico efforts demonstrated that the novel nanochelator is expected to improve the PK of DFO when compared to standard infusion regimens of native DFO. Moreover, reasonable formulation strategies were identified and discussed for both early clinical development and more sophisticated formulation development.