Abstract: ORIGINAL RESEARCH published: 16 June 2021 doi: 10.3389/fmedt.2021.687681 Low Acyl Gellan as an Excipient to Improve the Sprayability and Mucoadhesion of Iota Carrageenan in a Nasal Spray to Prevent Infection With SARS-CoV-2 Thomas E. Robinson, Richard J. A. Moakes and Liam M. Grover* Healthcare Technologies Institute, School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom Edited by: Anthony Bull, Imperial College London, United Kingdom Reviewed by: Canhui Yang, Southern University of Science and Technology, China Kobra Omidfar, Tehran University of Medical Sciences, Iran *Correspondence: Liam M. Grover l.m.grover@bham.ac.uk Specialty section: This article was submitted to Diagnostic and Therapeutic Devices, a section of the journal Frontiers in Medical Technology Received: 29 March 2021 Accepted: 20 May 2021 Published: 16 June 2021 Citation: Robinson TE, Moakes RJA and Grover LM (2021) Low Acyl Gellan as an Excipient to Improve the Sprayability and Mucoadhesion of Iota Carrageenan in a Nasal Spray to Prevent Infection With SARS-CoV-2. Front. Med. Technol. 3:687681. doi: 10.3389/fmedt.2021.687681 The COVID-19 global pandemic, as well as the widespread persistence of influenza and the common cold, create the need for new medical devices such as nasal sprays to prevent viral infection and transmission. Carrageenan, a sulfated polysaccharide, has a broad, non-pharmacological antiviral capacity, however it performs poorly in two key areas; spray coverage and mucoadhesion. Therefore gellan, another polysaccharide, was investigated as an excipient to improve these properties. It was found that viscoelastic relaxation time was the key predictor of spray coverage, and by reducing this value from 2.5 to 0.25 s, a mix of gellan and carrageenan gave more than four times the coverage of carrageenan alone (p < 0.0001). Gellan also demonstrated enhanced adhesion to a mucus analog that increased significantly with time (p < 0.0001), suggesting the development of specific gellan–mucin interactions. This property was conferred to carrageenan on mixing the two polymers. Together, this data suggests that gellan is a promising excipient to improve both sprayability and mucoadhesion of carrageenan for use in antiviral nasal sprays. Keywords: antiviral polymer, nasal spray, mucoadhesion, gellan, carrageenan, COVID-19