Fabio Fais and colleagues developed and tested a bentonite-containing nasal spray (AM-301) that could protect against SARS-CoV-2 and other airborne pathogens. They showed that it is not only safe but also it significantly decelerated viral titer growth in experimental models of prophylaxis and mitigation. Their study recently appeared in bioRxiv.
The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Detection of the virus was first reported in Wuhan, China and has since spread worldwide, emerging as a global pandemic. During the first days of SARS-CoV-2 infection and other respiratory viruses, the nasal tract has a high viral load than throat swabs. The same distribution was observed in an asymptomatic patient, implicating the nasal epithelium as a portal for initial infection and transmission. Therefore, the nose is important target of prophylactic and therapeutic interventions against these viruses.
Bentonite is a clay mineral composed of thin aluminum silicate sheets with a net negative charge; these properties contribute to its ability to adsorb viral particles and molecules such as drugs. Thus, Fabio Fais and colleagues hypothesized that a bentonite-containing nasal spray could protect against SARS-CoV-2 and other airborne pathogens.
“Bentonite suspensions can have thixotropic properties, that is, they reversibly change from a gel when undisturbed to a fluid colloid when agitated. We envisioned a bentonite-containing nasal spray that could be applied as a liquid, but in the nasal cavity it would form a durable, protective gel barrier.”
They therefore devised a bentonite-containing nasal spray (AM-301, Bentrio) with the aim of providing a safe and effective means of self-protection against exposure to harmful airborne particles.
Later, they tested the safety and efficacy of nasal spray against SARS-CoV-2 infection on an in vitro 3D model of primary human nasal airway epithelium.
“Safety was assessed in assays for tight junction integrity, cytotoxicity and cilia beating frequency. Efficacy against SARS-CoV-2 infection was evaluated in prophylaxis and infection mitigation assays.”
They showed that, product (nasal spray) didn’t have any adverse effects on the nasal epithelium. In addition, prophylactic treatment with product reduced viral titer significantly vs. controls over 4 days, reaching a maximum reduction of 99%. Moreover, when treatment with product was started 24 or 30 h after infection, epithelia that received the formulation had a 12- or 14-fold lower titer than controls.
All these results suggested that the product is safe in vitro and it significantly decelerated viral titer growth in experimental models of prophylaxis and mitigation.
Reference: Fabio Fais, Reda Juskeviciene, Veronica Francardo, Stéphanie Mateos, Samuel Constant, Massimo Borelli, Ilja P. Hohenfeld, Thomas Meyer, “Drug-free nasal spray as a barrier against SARS-CoV-2 infection: safety and efficacy in human nasal airway epithelia”, bioRxiv 2021.07.12.452021; doi: https://doi.org/10.1101/2021.07.12.452021
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