Onradivir monohydrate  (Synonyms: ZSP1273 monohydrate)

Onradivir (ZSP1273) monohydrate is an orally active antiviral agent targeting influenza A virus RNA polymerase PB2 subunit with an IC₅₀ of 0.562 nM. Onradivir monohydrate inhibits cap binding to influenza A virus RNA polymerase PB2 subunit, suppresses viral replication, reduces viral titres and RNA loads, and inhibits influenza A virus infection. Onradivir monohydrate maintains high survival rates in influenza A virus-infected mice, and reduces influenza A virus titers in a murine model. Onradivir monohydrate can be used for the research of influenza A virus infection^[1][2].

Onradivir (0.457-1000 nM; 24 h post-6-hour transfection) monohydrate potently inhibits influenza A virus polymerase activity in HEK293T cells, with a mean IC₅₀ of 0.562 nM^[2].
Onradivir (0.17-10,000 nM) monohydrate does not inhibit most tested human kinases at concentrations up to 10,000 nM, with only weak activity against Aurora A kinase (IC₅₀ = 527 nM)^[2].
Onradivir (0.0005-100 μM; 2-5 days) monohydrate potently inhibits replication of wild-type, Oseltamivir (HY-13317)-resistant, and Baloxavir (HY-109025A)-resistant influenza A strains in MDCK cells (EC₅₀ 0.012-0.063 nM) with high selective index, and shows weak activity against HRV-1B (EC₅₀ 7.88 μM) in H1 HeLa cells^[2].
Onradivir (48 h post-virus infection) monohydrate potently inhibits replication of highly pathogenic avian influenza H7N9 and H5N6 viruses in MDCK cells, with IC₅₀ values ranging from 0.245-0.777 nM^[2].
Onradivir (10 μM; 3 days) monohydrate does not inhibit HCV genotype 1b replicon replication or cause cytotoxicity at concentrations up to 10 μM^[2].
Onradivir (0.16-40 μM; 1 min per concentration) monohydrate does not significantly inhibit hERG potassium channel function in CHO cells at concentrations up to 40 μM (IC₅₀ >40 μM)^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Onradivir (ZSP1273) (3-30 mg/kg; p.o.; twice daily; days 1-2 to days 1-4) monohydrate dose-dependently reduces lung viral titers and supports body weight recovery in influenza A virus WSN/33 (H1N1)-infected female BALB/c mice when administered starting 36 h post-infection, with the 30 mg/kg dose reducing viral titers below the limit of detection^[2].
Onradivir (ZSP1273) (10 mg/kg; p.o.; twice daily; 7 days) monohydrate provides 100% survival when administered 4 h pre-infection, improves survival when administered 48 h post-infection, provides partial survival when administered 72 h post-infection, and extends time to death when administered 96 h post-infection in influenza A virus WSN/33 (H₁N₁)-infected female BALB/c mice^[2].
Onradivir (ZSP1273) (30-100 mg/kg; p.o.; twice daily; 7 days) monohydrate provides 100% survival at 30 mg/kg, and provides high survival with minimal deaths at 100 mg/kg, when administered starting 48 h post-infection in influenza A virus WSN/33 (H1N1)-infected female BALB/c mice^[2].
Onradivir (ZSP1273) (25 mg/kg; p.o.; twice daily; 5 days) monohydrate significantly reduces nasal lavage viral load and maintains stable body weight in influenza A virus/California/07/2009 (H1N1)-infected female ferrets when administered starting 4 h pre-infection^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

458.46

C₂₂H₂₄F₂N₆O₃

2375241-19-1

FC1=CN=C2C(C(C3=NC(N[C@@H]4[C@H](C5CCC4CC5)C(O)=O)=C(F)C(C6CC6)=N3)=NN2)=C1.O

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Li J, et al. Onradivir: a novel influenza polymerase inhibitor. Lancet Respir Med. 2025 Jul;13(7):571-573.  [Content Brief]

  [2]. Chen X, et al. Preclinical Study of ZSP1273, a Potent Antiviral Inhibitor of Cap Binding to the PB2 Subunit of Influenza A Polymerase. Pharmaceuticals (Basel). 2023;16(3):365. Published 2023 Feb 27.  [Content Brief]