VV261 (at a concentration of up to 200 µM) effectively inhibited CCHFV infection in HUVEC cells, with an EC50 value of 2.72 µM. It exhibited extremely low cytotoxicity and a selectivity index greater than 73.53 [1]. VV261 (2-50 µM) inhibited the activity of CCHFV RdRp in BSR-T7/5 cells in a dose-dependent manner [1]. VV261 (48 hours) effectively inhibited SFTSV replication in Vero-ATCC cells, with an EC50 value of 0.89 μM [2]. VV261 (48 hours) effectively inhibited LCMV replication in A549 cells, with an EC50 value of 0.15 μM [2].

VV261 (1–10 mg/kg; orally; once daily for 6 days) inhibited viral replication in a mouse model of lethal Crimean-Congo hemorrhagic fever virus (CCHFV) [1]. VV261 (2.5–10 mg/kg; orally; once daily for 7 days) showed dose-dependent efficacy against polio Behçet's virus (SFTSV) in IFNAR1tm1Agt mice [2]. VV261 (1–5 mg/kg; orally; once daily for 7 days) showed dose-dependent efficacy against lymphocytic choroid plexus meningitis virus (LCMV) in C57BL/6-Prf1tm1Sdz/J mice [2].

Real-time quantitative PCR[2]
Cell Types: A549 cells
Tested Concentrations: /
Incubation Duration: 48 hours
Experimental Results: Inhibited LCMV replication, EC50 was 0.15 μM. No measurable cytotoxicity was observed at concentrations up to 100 μM, with a selectivity index >667.

Animal/Disease Models:A129 mice (IFNα/β receptor deficient) (10-week-old males, intraperitoneally injected with 10 TCID50 CCHFV) [1]
Doses: 1 mg/kg; 5 mg/kg; 10 mg/kg
Route of Administration: Oral; once daily; for 6 consecutive days
Experimental Results: No significant weight loss was observed in the 5 mg/kg and 10 mg/kg dose groups during the observation period, the survival rate was 100%, and the viral load in the liver and spleen tissues was almost undetectable. Compared with the vector control group, the 1 mg/kg dose group showed delayed weight loss and prolonged survival time, but did not achieve complete protection, and the viral load inhibition effect in the liver and spleen tissues was poor. Significantly reduced liver tissue damage (reduced hepatocyte necrosis and lymphocyte filtration) and protected spleen structure (5 mg/kg and 10 mg/kg doses).

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Animal/Disease Models:IFNAR1tm1Agt mice (6-8 weeks old; intraperitoneal injection of 1000 PFU SFTSV) [2]
Doses: 2.5 mg/kg; 5 mg/kg; 10 mg/kg
Route of Administration: Oral; once daily; for 7 days
Experimental Results: The survival rate was 16.7% in the 2.5 mg/kg dose group and 10 mg/kg in both the 5 mg/kg and 10 mg/kg dose groups. The 2.5 mg/kg dose group caused an initial decrease in body weight in mice, but the weight returned to normal by day 6; the 5 mg/kg and 10 mg/kg dose groups prevented the decrease in body weight. Platelet count and lymphocyte percentage recovered to near normal levels in a dose-dependent manner. Viral RNA copy number decreased in a dose-dependent manner. Compared with the control group, the 2.5 mg/kg dose group showed a significant reduction in infectious viral titers; on day 2 post-infection, viral titers in multiple organs in both the 5 mg/kg and 10 mg/kg dose groups decreased below the detection limit. Splenic tissue lesions improved in all dose groups, with normal spleen structure, clear red/white pulp boundary, dense and orderly arranged lymphocytes in the white pulp, and no necrosis or significant inflammatory cell infiltration observed.

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Animal/Disease Models:C57BL/6-Prf1tm1Sdz/J mice (intraperitoneal injection of 20,000 PFU LCMV) [2]
Doses: 1 mg/kg; 2.5 mg/kg; 5 mg/kg
Route of Administration: Oral; once daily; for 7 days
Experimental Results: 100% survival was achieved at all tested doses. Weight loss was prevented at all tested doses. Platelet count and lymphocyte percentage returned to near normal levels in all treatment groups. Viral RNA copy number decreased in a dose-dependent manner in the spleen, liver, lungs and kidneys, and all dose groups were more effective than the control group on day 5 post-infection. Infectious viral titers in the spleen, liver, lungs, and kidneys decreased in a dose-dependent manner; on day 5 post-infection, viral titers in both the 2.5 mg/kg and 5 mg/kg dose groups decreased below the detection limit, which was superior to the control group. All dose groups significantly improved splenic tissue lesions, with the spleen structure essentially returning to normal, the red pulp/white pulp boundary clearly defined, and no obvious necrosis or inflammatory cell infiltration.

[1]. Oral VV261 administration protects mice from lethal Crimean-Congo hemorrhagic fever virus challenge. J Virol. 2025 Dec 23;99(12):e0158325.

[2]. Design and Development of a Novel Oral 4'-Fluorouridine Double Prodrug VV261 against SFTSV. J Med Chem. 2025;68(9):9811-9826.

C28H34FN3O11

607.58

3003864-86-3

White to light yellow solid

O=C(C1=CC=CN=C1)OCN2C(N(C=CC2=O)[C@@H]3O[C@@](COC(C(C)C)=O)(F)[C@@H](OC(C(C)C)=O)[C@H]3OC(C(C)C)=O)=O

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: 本产品在运输和储存过程中需避光（避免光照）。

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 100 mg/mL (~164.59 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)