Authors :
Presenting Author: Viktoriya Mashinson, PhD – University of Nebraska Medical Center
Martin Conda-Sheridan, PhD – University of Nebraska Medical Center
Olga Taraschenko, MD – Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE
Rationale:
Anti-NMDA receptor encephalitis (anti-NMDARE) is characterized by rapid cognitive decline and seizures that respond poorly to conventional therapies; novel effective treatments are urgently needed. We developed and extensively characterized a mouse model of NMDARE in which intracranial infusion of monoclonal antibodies derived from affected patients precipitates seizures and memory loss in mice. Further, we showed that blocking IL-1 receptor (IL-1R)-mediated signaling by administration of anakinra, a recombinant IL-1R antagonist (IL-1Ra), attenuates seizures and improves memory in mice. However, the large size of the IL-1Ra protein and its pharmacokinetic properties limit its ability to cross the blood-brain barrier (BBB). To address this critical need, we developed a cationic noisome, a vesicular drug carrier, for efficient intranasal delivery of IL-1Ra to the brain. To enable direct visualization of the drug's distribution in the brain, we further enhanced the carrier by incorporating a fluorescent tag into the niosomal membrane.
Methods:
The niosomes were prepared using variable amounts of sorbitan trioleate (Span-85), cholesterol, and a synthetic Bodipy fluorescent dye via the thin film hydration method. The niosomes were loaded with IL-1Ra in phosphate buffer, then sonicated, centrifuged, filtered, and washed. Zeta potential was measured using a zeta potential analyzer, while effective diameter and polydispersity index (PDI) was determined using dynamic light scattering (DLS). Niosome size and morphology were characterized via transmission electron microscopy (TEM), and qualitative drug release was assessed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) imaging. The fluorescent tag was incorporated into the niosomal membrane, enabling detection with a 365 nm long-wave ultraviolet lamp.
Results:
The TEM images of the IL-1Ra-loaded niosomes showed spherical morphology and the formation of bilayered vesicles. The mean diameter of the niosomes was 175.05 nm, falling within the optimal size (100–200 nm) for intranasal delivery according to prior studies. The PDI of the IL-1Ra-loaded niosomes was 0.143, indicating a uniform sample with a narrow size distribution. Qualitative release studies revealed free drug in the supernatant at 20 and 48 hours, suggesting the IL-1Ra release over time. Quantitative assessment of IL-1Ra release using high-performance liquid chromatography is ongoing. Future modifications aim to impart a positive surface charge to enhance nasal mucosal penetration. The effects of intranasally delivered IL-1Ra-loaded niosomes on antibody-induced seizures and memory function will be evaluated in our mouse model.
Conclusions:
We successfully developed a novel, fluorescently labeled niosomal carrier for IL-1Ra delivery. Notably, we established a method for formulating niosomes with physicochemical properties conducive to intranasal transport and demonstrated drug release sustained up to 48 hours. This innovative carrier system has the potential to penetrate the BBB and deliver polar molecules like IL-1Ra into the brain. Additionally, we incorporated a fluorescent dye that allows for in vivo visualization of the delivery vehicle.
Funding: N/A