A Throat Lozenge with Fixed Combination of Cetylpyridinium Chloride and Benzydamine Hydrochloride Has Direct Virucidal Effect on SARS-CoV-2

Abstract

Viruses are the most common causative agents of inflammation in the oral cavity and throat region. Most respiratory tract infections are self-limiting and require no specific treatment. However, patients often use different self-medication therapies that can treat both the symptoms and the cause. Throat lozenges with a fixed combination of benzydamine hydrochloride and cetypiridinium chloride (BH/CPC) have been shown to provide effective symptomatic relief for sore throat, but their effect on viruses has not been investigated to date. The antiseptic, cetylpyridinium chloride (CPC), has already been described as a successful bactericide. In addition, there are some studies suggesting its efficacy against certain enveloped viruses. Thus, the aim of our study was to examine the virucidal activity of CPC and a combination of BH/CPC as a free active substance or as lozenge on SARS-CoV-2 in vitro. Under in-laboratory simulated conditions of lozenge administration, we incubated SARS-CoV-2 with three different concentrations of each of the active substances, CPC, free BH/CPC or BH/CPC, as a lozenge suspension for 1 min, 5 min and 15 min of contact time. Infective viral particles were detected in cell cultures and the viral titre was calculated accordingly. Our results show that all active substances in high-concentration suspensions, as well as a medium concentration of the BH/CPC combination, exhibited a 4-log reduction in viral titre. Additionally, the highest concentration of BH/CPC as a lozenge had a faster virucidal effect compared to CPC as a free active substance alone, since a contact time as short as 1 min reduced the initial virus concentration by more than 4-log. This study demonstrates the effective strong virucidal effect of the lozenge, with the possibility of viral load reduction in the oral cavity and, consequently, reduced risk of viral transmission.