Virucidal activity and mechanism of action of cetylpyridinium chloride against SARS-CoV-2

An exploratory study of drug concentration and inhibitory effect of cetylpyridinium chloride buccal tablets on SARS-CoV-2 infection among 10 Chinese subjects

BACKGROUND

It was evidenced that cetylpyridinium-chloride (CPC) mouthwash could inhibit SARS-COV-2 activity and reduce salivary viral load, thus reducing SARS-CoV-2 transmission. However, due to insufficient residence time in the oral cavity, CPC-containing mouthwashes have no prolonged antiviral effect. The duration of action of the CPC buccal tablet is expected to be longer than that of the mouthwash. However, there are currently no reports on the salivary drug concentration of CPC buccal tablets.

OBJECTIVE

The study aimed to investigate the salivary drug concentration of CPC buccal tablets and the antiviral effect of CPC on SARS-CoV-2 in vitro.

TRIAL DESIGN

This is a single-dose, single-arm clinical trial, involving 10 Chinese healthy subjects who received 2-mg CPC buccal tablet to collect saliva samples and to detect saliva concentration at different timepoints within 2 h (Clinical Trial Registration Number: NCT05802628, Registration Date: April 6, 2023).

MATERIALS AND METHODS

CPC concentration in saliva was detected by liquid chromatography tandem mass spectrometry (LC-MS/MS), and pharmacokinetic parameters were calculated based on the non-compartmental model. With an in vitro antiviral experiment, the activity of CPC buccal tablets against SARS-CoV-2 and its cellular toxicity was tested.

RESULTS

Drug concentrations in saliva at 15 min, 30 min, 1 h, 1.5 h, and 2 h after administration were 8008.33 (1042.25, 41081.11), 2093.34 (373.15, 5759.83), 1016.58 (378.66, 3480.68), 891.77 (375.66, 6322.07), and 717.43 (197.87, 2152.71) ng/mL. PK parameters of saliva concentration: Cmax = 8008.33 (1042.25, 41081.11) ng/mL, AUC0-t = 4172.37 (904.42, 13912.61) ng/mL * h, AUC0-∞ = 6712.85 (1856.77, 19971.12) ng/mL * h, T1/2 = 1.22 (0.59, 2.83) h, Tmax = 0.25 (0.25, 0.25) h. As determined in in vitro experiment, CPC was active on SARS-CoV-2 with cytotoxic and inhibitory activity of CC50 = 35.75 μM (≈12155 ng/mL) and EC50 = 7.39 μM (≈2512.6 ng/mL).

CONCLUSIONS

The comparison between the salivary CPC concentration and EC50/CC50 values from in vitro antiviral experiments suggests that CPC buccal tablets may inhibit SARS-CoV-2 activity, and the inhibition may last for approximately 30 min without cytotoxicity.

Reduction of SARS-CoV-2 viral load in saliva after rinsing with mouthwashes containing cetylpyridinium chloride: a randomized clinical study

Background

Symptomatic patients with COVID-19 typically have a high SARS-CoV-2 viral load in their saliva. Procedures to reduce the viral load in their oral cavity are important for mitigating the viral transmission.

Methods

This randomized clinical trial investigated the impact of two mouthwashes (0.075% cetylpyridinium chloride plus 0.28% zinc lactate (CPC+Zn) (n = 32), and 0.075% cetylpyridinium chloride (CPC) (n = 31)) on the viral load of SARS-CoV-2 in saliva when compared to the distilled water negative control (n = 32). Saliva was collected before (T0) and after (5 min, T1; 30 min, T2; and 60 min, T3) the intervention. Viral load in saliva was measured by qRT-PCR assays. The data in both groups was normalized for T0 and Negative Control, resulting in fold change values.

Results

CPC+Zn oral solution reduced the viral load in saliva by 6.34-fold at T1, 3.6-fold at T2 and 1.9-fold at T3. Rinsing with the CPC mouthwash reduced the viral load in saliva by 2.5-fold at T1, 1.9-fold at T2 and 2.0-fold at T3.

Conclusion

CPC+Zn mouthwash or with the CPC mouthwash reduced the viral load in saliva of COVID-19 patients immediately after rinsing. These reductions extended up to 60 min.

Efficacy of different mouthwashes against COVID-19: A systematic review and network meta-analysis

To evaluate the effectiveness of antiseptic mouthwashes in reducing SARS-CoV-2 load clinically and in vitro. A systematic electronic search (MEDLINE/Scopus/Cochrane) was conducted to identify prospective clinical and in vitro studies published between 2019 included and 16 June 2023 assessing the effectiveness of mouthwashes in reducing SARS-CoV-2 load in saliva or surrogates. Data were summarized in tables and a network meta-analysis was performed for clinical trials. Thirty-five studies (14 RCTs, 21 in vitro) fulfilled the inclusion criteria. The risk of bias was judged to be high for 2 clinical and 7 in vitro studies. The most commonly test product was chlorhexidine alone or in combination with other active ingredients, followed by povidone-iodine, hydrogen peroxide and cetylpyridinium chloride. Overall, the descriptive analysis revealed the effectiveness of the mouthwashes in decreasing the salivary viral load both clinically and in vitro. Network meta-analysis demonstrated a high degree of heterogeneity. Among these studies, only chlorhexidine 0.20% was associated to a significant Ct increase in the saliva 5 min after rinsing compared to non-active control (p = 0.027). Data from clinical and in vitro studies suggested the antiviral efficacy of commonly used mouthwashes. Large well-balanced trials are needed to identify the best rinsing protocols.

Discovery of PLpro and Mpro Inhibitors for SARS-CoV-2

There are very few small-molecule antivirals for SARS-CoV-2 that are either currently approved (or emergency authorized) in the US or globally, including remdesivir, molnupiravir, and paxlovid. The increasing number of SARS-CoV-2 variants that have appeared since the outbreak began over three years ago raises the need for continual development of updated vaccines and orally available antivirals in order to fully protect or treat the population. The viral main protease (Mpro) and the papain-like protease (PLpro) are key for viral replication; therefore, they represent valuable targets for antiviral therapy. We herein describe an in vitro screen performed using the 2560 compounds from the Microsource Spectrum library against Mpro and PLpro in an attempt to identify additional small-molecule hits that could be repurposed for SARS-CoV-2. We subsequently identified 2 hits for Mpro and 8 hits for PLpro. One of these hits was the quaternary ammonium compound cetylpyridinium chloride with dual activity (IC50 = 2.72 ± 0.09 μM for PLpro and IC50 = 7.25 ± 0.15 μM for Mpro). A second inhibitor of PLpro was the selective estrogen receptor modulator raloxifene (IC50 = 3.28 ± 0.29 μM for PLpro and IC50 = 42.8 ± 6.7 μM for Mpro). We additionally tested several kinase inhibitors and identified olmutinib (IC50 = 0.54 ± 0.04 μM), bosutinib (IC50 = 4.23 ± 0.28 μM), crizotinib (IC50 = 3.81 ± 0.04 μM), and dacominitinib (IC50 = IC50 3.33 ± 0.06 μM) as PLpro inhibitors for the first time. In some cases, these molecules have also been tested by others for antiviral activity for this virus, or we have used Calu-3 cells infected with SARS-CoV-2. The results suggest that approved drugs can be identified with promising activity against these proteases, and in several cases we or others have validated their antiviral activity. The additional identification of known kinase inhibitors as molecules targeting PLpro may provide new repurposing opportunities or starting points for chemical optimization.

Antiviral and antibacterial activity of sodium alginate/poly(diallyldimethylammonium chloride) polyelectrolyte film for packaging applications

Pathogen agents, such as bacteria and virus, can contaminate plastic surfaces, particularly those used in food packaging. This study proposed to prepare a polyelectrolyte film with antiviral and antibacterial activity based on sodium alginate (SA) and poly(diallyldimethylammonium chloride) (PDADMAC), a cationic polymer with sanitizing properties. In addition, the physicochemical properties of the polyelectrolyte films were also evaluated. The polyelectrolyte films showed continuous, compact, and crack-free structures. The FTIR analysis confirmed the ionic interaction between SA and PDADMAC. Adding PDADMAC significantly affected the mechanical properties of the films (p < 0.05), increasing the maximum tensile strength (from 8.66 ± 1.55 MPa to 18.1 ± 1.77 MPa). However, polyelectrolyte films showed higher water vapor permeability values due to the strong hydrophilicity of PDADMAC, representing a 43 % average increase compared with the control film. Also, thermal stability improved with the incorporation of PDADMAC. The selected polyelectrolyte film inactivated 99.8 % of SARS-CoV-2 after 1 min in direct contact with the virus, in addition to having an inhibitory effect against Staphylococcus aureus and Escherichia coli bacteria. Therefore, this study demonstrated the efficacy of using PDADMAC in the preparation of polyelectrolyte sodium alginate-based films with improvements in physicochemical properties and especially with antiviral activity against SARS-CoV-2.

Efficacy of Cetylpyridinium Chloride mouthwash against SARS-CoV-2: A systematic review of randomized controlled trials

INTRODUCTION

COVID-19 is a transmissible respiratory and multisystem disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Viral transmission occurs mainly through the spread of salivary droplets or aerosol from an infected subject. Studies suggest that salivary viral load is correlated with disease severity and probability of transmission. Cetylpyridinium chloride mouthwash has been found to be effective in reducing salivary viral load. The aim of this systematic review of randomized controlled trials is to evaluate the efficacy of the mouthwash ingredient cetylpyridinium chloride on salivary viral load in SARS-CoV-2 infection.

METHODS

Randomized controlled trials comparing cetylpyridinium chloride mouthwash with placebo and other mouthwash ingredients in SARS-CoV-2 positive individuals were identified and evaluated.

RESULTS

Six studies with a total of 301 patients that met the inclusion criteria were included. The studies reported the efficacy of cetylpyridinium chloride mouthwashes in reduction on SARS-CoV-2 salivary viral load compared to placebo and other mouthwash ingredients.

CONCLUSION

Mouthwashes containing cetylpyridinium chloride are effective against salivary viral load of SARS-CoV-2 in vivo. There is also the possibility that the use of mouthwash containing cetylpyridinium chloride in SARS-CoV-2 positive subjects could reduce transmissibility and severity of COVID-19.

The Role of Cyclodextrins in COVID-19 Therapy-A Literature Review

Coronavirus disease-19 (COVID-19) emerged in December 2019 and quickly spread, giving rise to a pandemic crisis. Therefore, it triggered tireless efforts to identify the mechanisms of the disease, how to prevent and treat it, and to limit and hamper its global dissemination. Considering the above, the search for prophylactic approaches has led to a revolution in the reglementary pharmaceutical pipeline, with the approval of vaccines against COVID-19 in an unprecedented way. Moreover, a drug repurposing scheme using regulatory-approved antiretroviral agents is also being pursued. However, their physicochemical characteristics or reported adverse events have sometimes limited their use. Hence, nanotechnology has been employed to potentially overcome some of these challenges, particularly cyclodextrins. Cyclodextrins are cyclic oligosaccharides that present hydrophobic cavities suitable for complexing several drugs. This review, besides presenting studies on the inclusion of antiviral drugs in cyclodextrins, aims to summarize some currently available prophylactic and therapeutic schemes against COVID-19, highlighting those that already make use of cyclodextrins for their complexation. In addition, some new therapeutic approaches are underscored, and the potential application of cyclodextrins to increase their promising application against COVID-19 will be addressed. This review describes the instances in which the use of cyclodextrins promotes increased bioavailability, antiviral action, and the solubility of the drugs under analysis. The potential use of cyclodextrins as an active ingredient is also covered. Finally, toxicity and regulatory issues as well as future perspectives regarding the use of cyclodextrins in COVID-19 therapy will be provided.

Antimicrobial and Virucidal Potential of Morpholinium-Based Ionic Liquids

Witnessed by the ongoing spread of antimicrobial resistant bacteria as well as the recent global pandemic of the SARS-CoV-2 virus, the development of new disinfection strategies is of great importance, and novel substance classes as effective antimicrobials and virucides are urgently needed. Ionic liquids (ILs), low-melting salts, have been already recognized as efficient antimicrobial agents with prospects for antiviral potential. In this study, we examined the antiviral activity of 12 morpholinium based herbicidal ionic liquids with a tripartite test system, including enzyme inhibition tests, virucidal activity determination against five model viruses and activity against five bacterial species. The antimicrobial and enzymatic tests confirmed that the inhibiting activity of ILs corresponds with the number of long alkyl side chains and that [Dec₂Mor]⁺ based ILs are promising candidates as novel antimicrobials. The virucidal tests showed that ILs antiviral activity depends on the type and structure of the virus, revealing enveloped Phi6 phage as highly susceptible to the ILs action, while the non-enveloped phages PRD1 and MS2 proved completely resistant to ionic liquids. Furthermore, a comparison of results obtained for P100 and P001 phages demonstrated for the first time that the susceptibility of viruses to ionic liquids can be dependent on differences in the phage tail structure.