Study of the Mechanism of Antiviral Activity of Cytovir®-3 Against Respiratory Viruses In Vitro

Introduction . The requirements of modern clinical guidelines for the treatment of respiratory viral infections suggest the possibility of identifying a specific viral pathogen. In this regard, the search for drugs with selective activity against respiratory syncytial virus and parainfluenza virus is relevant. The purpose of the work is to study the antiviral activity of the drug Cytovir®-3 in vitro in relation to the cytopathogenic effect of respiratory viruses (parainfluenza virus and respiratory syncytial virus). Material and methods . The antiviral effect of Cytovir®-3 in comparison with Umifenovir against parainfluenza virus and respiratory syncytial virus was studied on Vero cell culture. Drugs were administered 1 hour before (prophylactic regimen) and 1 hour after (treatment regimen) infection of the cell culture with respiratory viruses. The working range of concentrations of the studied drugs was calculated based on the values of 50% cytotoxic concentration calculated based on the results of a quantitative microtetrazole test. Results and discussion. The drug Cytovir®-3 in two schemes of application (therapeutic or prophylactic) showed its antiviral efficacy in vitro against respiratory syncytial virus and parainfluenza virus due in the non-toxic range (0–794 µg/ml). At the same time, the suppressive effect of the drug Cytovir®-3 against the parainfluenza virus begins at lower concentrations of the drug with its early (preventive) introduction into cell culture (250 mcg/ml). Conclusion . Antiviral activity of Cytovir®-3 has been proven in vitro against parainfluenza virus and respiratory syncytial virus. At the same time, in all series of experiments, Cytovir®-3 had a higher index of selectivity of antiviral action than that of the comparison drug Umifenovir.