Erythromycin estolate is a semi-synthetic derivative of erythromycin with good oral absorption and bioavailability tolerance. As a macrolide antibiotic, Erythromycin exerts its antibacterial action by inhibiting bacterial protein synthesis and is mainly used in studies for the treatment of respiratory, skin and soft tissue infections caused by susceptible bacteria. Erythromycin estolate may cause liver injury, including mild cholestatic hepatitis, jaundice, and paucity of bile ducts.

Erythromycin estolate effectively inhibited HCoV-OC43 infection in different cell types and significantly reduced virus titers at safe concentration without cell cytotoxicity. Furthermore, erythromycin estolate was identified to inhibit HCoV-OC43 infection at the early stage and to irreversibly inactivate virus by disrupting the integrity of the viral membrane whose lipid component might be the target of action. Together, it was demonstrated that erythromycin estolate could be a potential therapeutic drug for HCoV-OC43 infection.[1]