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Favipiravir (6-fluoro-3-hydroxy-2-pyrazinecarboxamide) is a purine nucleic acid analog, which is an antiviral agent used in the treatment of influenza. Since the recent outbreak caused by 2019-novel coronavirus (nCoV), there has been a seek for effective antiviral agents to be used in the treatment of coronavirus disease 2019 (COVID-19), and favipiravir has been one of the options which provides a broad-spectrum therapy. Herein, we studied the aqueous solubility and in vitro permeability characteristics of favipiravir in order to shed light on the BCS classification of this antiviral agent used in COVID-19 therapy. The in vitro solubility was assessed using saturated solution of favipiravir in four different aqueous media and the solubility values were evaluated during 72 h at 37 oC. The solubility of favipiravir was between 4.48 to 8.5 mg/ml, which is 5.85 to 10.63 times of calculated solubility limit. Caco-2 cell monolayers were utilized for the permeability assessment, and the drug solutions in three different concentrations including the highest dose required for bioequivalence exemption of the immediate release dosage form were applied. The effect of efflux transporters on the permeability of favipiravir was also determined using a P-gp inhibitor, Verapamil HCl. According to the data obtained from the in vitro studies, favipiravir can be considered as a representative of class I compound. [ABSTRACT FROM AUTHOR]

Viral infections represent a serious threat to the world population and are becoming more frequent. The search and identification of broad-spectrum antiviral molecules is necessary to ensure new therapeutic options, since there is a limited availability of effective antiviral drugs able to eradicate viral infections, and consequently due to the increase of strains that are resistant to the most used drugs. Recently, several studies on antimicrobial peptides identified them as promising antiviral agents. In detail, amphibian skin secretions serve as a rich source of natural antimicrobial peptides. Their antibacterial and antifungal activities have been widely reported, but their exploitation as potential antiviral agents have yet to be fully investigated. In the present study, the antiviral activity of the peptide derived from the secretion of Rana tagoi, named AR-23, was evaluated against both DNA and RNA viruses, with or without envelope. Different assays were performed to identify in which step of the infectious cycle the peptide could act. AR-23 exhibited a greater inhibitory activity in the early stages of infection against both DNA (HSV-1) and RNA (MeV, HPIV-2, HCoV-229E, and SARS-CoV-2) enveloped viruses and, on the contrary, it was inactive against naked viruses (PV-1). Altogether, the results indicated AR-23 as a peptide with potential therapeutic effects against a wide variety of human viruses. [ABSTRACT FROM AUTHOR]

For symptomatic congenital cytomegalovirus infections (CCMVI), the usefulness of changes in viral load during valganciclovir (VGCV) treatment for the prediction of hearing dysfunction (HD) is unclear. To determine the utility of viral load change in the whole blood or urine for the prediction of HD, we performed a retrospective study to compare viral load changes during VGCV treatment between CCMVI infants with (n = 12) or without (n = 8) HD at six months of corrected age, whose blood and urine viral loads were measured continuously for eight weeks from April 2009 to December 2019. There was no significant difference in the changes in both the blood and urine viral loads after the initiation of VGCV treatment between CCMVI infants between the groups. Moreover, this negative result was maintained in the analysis for each six weeks or six months treatment period. In conclusion, the change in viral load during antiviral therapy is not useful for the prediction of HD at six months of corrected age in symptomatic CCMVI. [ABSTRACT FROM AUTHOR]