Identification of Diphenoxylate as an Antiviral Agent Against Severe Acute Respiratory Syndrome Coronavirus 2

This is the first report to show that diphenoxylate is highly active against SARS-CoV-2 with EC₅₀ of 1.4 μM, CC₅₀ over 100 μM and selectivity index over 71.4 after screening of 14 diphenyl derivatives. Our results with highly purified solid diphenoxylate confirmatively demonstrate that the viral S protein is reduced in the virus-infected cells in a dose-dependent manner. It could provide insights for antiviral treatment of COVID-19 with diphenoxylate or its chemical derivatives