N3: Negative, Nerve-Targeted Nanocarriers

To defeat OP nerve agents, we must match both their potency and access to the synaptic cleft. Unfortunately, the most potent organophosphate antidotes cannot access neurons from the systemic circulation. Phosphotriesterase (PTE) enzyme mutants are too large, and small, cationic oximes are too charged to cross the blood-brain-barrier or blood-nerve-barrier in appreciable quantities. State-of-the-art PTE therapy requires weekly prophylactic use as a blood-based scavenger; immunogenicity concerns and costly recurring doses dim its prospects for success in the field. Similarly, standard medicinal chemistry techniques for enhancing oxime access to nerves (e.g. lipophilization, prodrug design, hijacking active transporters) have failed to bear fruit.  In this innovative effort, nSI will construct a library of 50 compositionally diverse, barcoded NPs co-encapsulating an enzymatically active PTE simulant and pralidoxime chloride with efficiencies >25%. All formulations will exhibit a monodisperse, monomodal size distribution (PDI < 0.25), a z-average hydrodynamic diameter < 200 nm, a zeta potential < 0 mV, stability in serum at 37oC, and high batch-to-batch reproducibility (size and zeta std of <15%). Leveraging cutting-edge nanoparticle barcoding advances, we will demonstrate the compatibility of all formulations with multiplexed in vivo PK/BD workflows using either stable metal isotope tagging or nucleic acid barcoding. Anticipating future FDA approval, we will utilize only polymers and lipids that are endogenous or in current clinical use. This constraint will not negatively impact our design space; recent research has demonstrated exquisite, tunable organ- and cell-specific tropism by varying single components of lipid/PEG-lipid/cholesterol formulations. To minimize risk, 5-10 formulations will be drawn from literature with demonstrated in vivo neurotropism. Rapid microfluidic formulation, multiplex DLS, and multiplex dialysis equipment enable this work to occur within the scope of a DHA Phase I award. The result will be a multiplexed, multidrug, anionic NP library that can be co-administered and rapidly screened for in vivo neurotropism in Phase II.