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SMIs and Soft Mist Nasal Sprays – A Key Defence in the Fight Against the Next Pandemic?

The COVID-19 outbreak has provided a number of lessons for the pharmaceutical industry to consider for future pandemics. Wilbur de Kruijf at Recipharm argues that one key takeaway must be to change the way vaccines are administered. Could soft mist inhalers (SMIs), and soft mist nasal sprays, in particular, hold the key to improved vaccine delivery?

Spotlighting the potential of messenger RNA (mRNA) vaccines to speed up vaccine development and the importance of inter-company partnerships, the COVID-19 pandemic has reinforced key learnings for the pharmaceutical industry.

Perhaps the most crucial lesson has been the value of collaboration with contract development and manufacturing organisations (CDMOs). With the formulation and upscaling support of these specialist partners, pharmaceutical companies had access to the infrastructure they needed to develop their vaccines at record speeds. They also benefited from the capacity to commercialise their products and deliver billions of doses, as well as expertise in solving cold-chain transport challenges. In addition, they had an insight into overcoming administration issues to minimise discomfort for patients.

With so many advances made in our efforts to tackle coronavirus, it is now time for us to look ahead, exploring what we can take away from the present to further improve our work developing vaccines to fight future pandemics. We need to consider how we can further streamline development, and how to improve commercialisation processes. Just as importantly, we need to think about how to enhance the administration of vaccines, perhaps without the need for patients to attend crowded vaccination centres.

Thanks to technological advances in recent years, one solution to this last challenge could be to use innovative soft mist inhalers (SMIs), and soft mist nasal spray device technology in particular, to harness the useability benefits of nasal vaccine delivery.

The Advantages of Nasal Administration

Parenteral administration has long been the standard approach when developing vaccines for two key reasons. First, formulation development is streamlined due to the enhanced bioavailability inherent to injected drugs. Second, efficacy is optimised as injection bypasses the defence mechanisms in the gastrointestinal tract that can damage the active ingredients within the vaccine.

Nevertheless, non-invasive administration routes are beginning to be explored for their ability to enhance the patient experience and potentially improve performance. A number of such routes have been investigated for delivery of biologics, including oral,1 buccal,2 transdermal,3 and inhalation,4 including nasal.5

The nasal route in particular is rapidly establishing itself as a viable alternative. As recent studies suggest, mucosal delivery of vaccines provides a better, longer-lasting effect than the traditional injection route,6,7 and can trigger robust protective immune responses at the predominant sites of pathogen infection. Inducing adaptive immunity at mucosal sites, involving secretory antibody responses and tissue-resident T cells, can prevent an infection, particularly from coronavirus and influenza viruses, from establishing itself in the first place. Other approaches may simply reduce the severity of the infection and protect against the development of disease symptoms.

Nasal administration may also allow the volume of the formulation needed per patient to be considerably reduced, helping to make more doses available sooner in the event of a pandemic without the need to increase manufacturing capacity.

Developing a nasal vaccine offers advantages in the regulatory arena over injectables. As nasal products are noninvasive and allow for more targeted delivery compared with parenteral, they potentially offer reduced side effects and a faster response.

For all of these reasons, we are seeing significant growth in the nasal vaccine segment, which is forecast to grow in value from $122.287 million in 2021 to more than $250.91 million by the end of the decade.8

Unique Development Challenges

The benefits of nasal vaccine administration are clear. Nevertheless, there are challenges facing pharmaceutical companies seeking to develop them. Failure to deal with these issues could undermine future growth in the segment.

One problem that needs to be addressed is that biologics, including vaccines, are fragile and vulnerable to damage when dispensed from a nasal spray or from a nebuliser. A study from the University of Amsterdam demonstrated that lipid nanoparticles, such as those used in mRNA vaccine formulations, can be harmed when administered by an oral inhalation nebuliser.9