By Gifty Immanuel
The nasal delivery of therapeutics and vaccines offers unparalleled advantages as compared to conventional routes. The annals of vaccinology would be incomplete without the mention of nasal insufflation of dried smallpox scabs, a precursor to our modern-day vaccines, and Nasya Karma, an ancient practice that involved instilling powders, herbs, oils, and potions through the nasal route.
The nasal pathway is a non-invasive and rapid method of therapeutic delivery. Further, the nose acts as a gateway for several pathogens; blocking their ingress at the portal of entry is a prudent prevention strategy. However, despite their versatility, these systems remain less explored.
Advantages of the Alternate Route
The anatomical proximity of the nose to the brain and lungs ensures rapid transit of drugs to the target site. Compared to intravenous, intra-arterial, intramuscular, subcutaneous, intra-rectal, and oral routes; a nasal route can instantaneously deliver the payload. It also bypasses the liver’s first pass metabolism and blood-brain barrier, resulting in better bioavailability. The rich vascularity and large surface area of the nose results in the quicker and complete absorption of drugs or vaccines.
Furthermore, since the intranasal route is the only route in the body with direct access to the brain, several neurotropic drugs can be delivered efficaciously via this route. Adverse reactions with intramuscular and intravenous formulations are rarely seen with nasal delivery of the same. Apart from these, social resistance to the administration of medicine and vaccines is a frequently encountered issue. It remains a barrier to drug and vaccine coverage. The nasal pathway can effectively circumvent this impediment by increasing the uptake of these therapeutics at the population level. Further, the risk of nosocomial infections like HIV, Hepatitis B, and Hepatitis C with traditional injections and unsterile techniques is non-existent with nasal delivery.
Stem Cells, Proteins, Peptides, Drugs, Insulins, and Biologicals Delivery
The nasal platform offers unprecedented drug delivery for local and systemic requirements. The plethora of drugs and biologicals includes, but is not limited to, stem cells, proteins, polypeptides, vaccines, immunoglobulins, antidepressants, psychiatric and neurotropic medications, corticosteroids, antihistamines, enzymes, and hormones. Intranasal insulin in particular is of significance as the global toll of diabetes is increasing exponentially. The nasal formulation can match the physiological doses secreted by the body, resulting in better sugar control. The nasal platform will be simple, easily deposited, and transported. The added benefit is that self-administered intranasal insulin is unlikely to cause hypoglycaemia or dangerously low blood sugar.
Similarly, cutting-edge therapies like stem cell transplants can use various nasal platforms. Multipotent self-renewing cells deposited in the nasal epithelium will eventually migrate and reach the brain. This approach offers an optimal approach to stem cell delivery. The prospects of success in treating neurodegenerative disorderslike Alzheimer’s, Parkinson’s, and many more through this novel approach are exciting. Apart from these, ongoing research offers evidence that neurological cancers like glioblastoma can be treated with nasal therapy.
Universal SARS CoV-2 Nasal Vaccine and Inactivated Nasal Polio Vaccine
SARS CoV-2 thwarts our efforts at disease control by immune evasion and constant mutations. This results in an incomplete response to vaccines and drugs. The protracted delays in viral elimination led to the loss of countless human lives. However, a novel step will be to use a Universal Polyvalent COVID-19 Vaccine through the nasal route. The nose is the major portal for the entry of the coronavirus; it will be a targeted strategy to increase nasal immunity. A multi-antigen universal COVID-19 vaccine will elicit sterilising or mucosal immunity, resulting in zero transmission. Such an approach offers immense hope to end this pandemic.
The recent polio outbreak in New York City highlights the importance of continued immunisation and surveillance. The oral vaccine with its live virus is understood to be the cause of this outbreak. With the inactivated nasal Polio vaccine, there is no risk of vaccine-derived Polio. Meanwhile, compared to the intramuscular Polio vaccine, the nasal Polio vaccine can elicit IgA immunoglobulin in the intestines and saliva, neutralising the virus on entry. Since Polio is an enteric disease transmitted by feco-oral contact, the nasal Polio vaccine can bolster the immune system, resulting in a blockade of gastrointestinal viral entry. The ease of mass delivery by vaccinators without formal training and the logistic advantages of this route cannot be overlooked. This applies to local outbreaks and pandemics on a global scale.
Smart Delivery Systems and Nasal Formulary
Controlled release nasal gels, microemulsions, suspensions, emulsions, nanotechnology, and a plethora of delivery devices like single, metered dose spray pumps, and nebulizers ensure uniform nasal deposition. The particle size, volume, and aerosol dynamics are controlled for optimal delivery. A variety of strategies like nasal mucoadhesion are used to enhance absorption against the flushing actions of the nasal secretions and mucociliary defences. These innovative approaches in rhinology have enhanced the nasal delivery of drugs for local and systemic conditions.
There is robust evidence that the nasal platform offers unmatched efficacy as a drug delivery vehicle. It is simple, fast, reliable, and practical. However, the clinical application and the large-scale use of nasal platforms remain underexplored. Advancements in material science and aerosol dispersion can further refine the utility of these systems. At Synergia Biosciences, we have developed and patented an advanced nanotechnology platform that can deliver any lipophilic drug to the central nervous system. Nasal delivery platforms can address existing diseases and emerging ones. As medical and public health tools, they await global utilisation.