Julie D. Suman, Ph.D.1
1Next Breath, an Aptar Pharma company, 1450 South Rolling Road, Baltimore, Maryland / 21045, USA
Summary
Chemoreceptors, trigeminal parasympathetic pathways and lymphatic tissue within the nasal cavity represent the future of nasal drug delivery. Targeted deposition in specific regions to deliver medication to these sites is growing. Unmet needs in CNS conditions such as Parkinsons Disease, Alzheimer’s and brain cancers like glioblastoma, all my benefit from drug transport along the olfactory neurons into the cerebral spinal fluid (CSF) or brain. Narrow spray plumes and optimized instructions for use help to direct droplets to the region of interest. For example, an increase in insertion depth of the spray nozzle may improve deposition in the olfactory regions by ~30%. However, deposition alone may not be enough. Formulation strategies to overcome mucociliary clearance are being investigated to improve retention. In addition, certain mucoadhesive excipients may also potentiate the immune response for intranasal vaccine. Nanoparticulate systems have the potential for both intranasal vaccination and improving uptake in the CNS via the olfactory nerves. The optimal nanoparticle size is being investigated as well as the potential toxicity associated from increased uptake in the brain. In vitro nasal casts and imaging studies have been instrumental in understanding intranasal deposition. Additional learnings from in silico models is also advancing the understanding of targeted nasal drug delivery.