title: Why aren't antivirals effective when administered intranasally?
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004848:Epithelium / Q000382:microbiology; D005289:Ferrets; D006146:Guanidines / Q000627:therapeutic use; D051379:Mice; D009924:Organ Culture Techniques; D012137:Respiratory System / Q000382:microbiology; D013997:Time Factors; D014132:Trachea; D014779:Virus Replication
chemical_list: D000998:Antiviral Agents; D006146:Guanidines