| Size | Price | Stock | Qty |
|---|---|---|---|
| 100mg |
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| 250mg |
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| 500mg |
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| 1g |
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| Other Sizes |
| Targets |
Favipiravir is a prodrug that is ribosylated and phosphorylated to the active triphosphate, which inhibits viral RNA-dependent RNA polymerase (RdRp). Impurity 5 may have altered fluorine substitution or a hydroxyl group that prevents proper ribosylation, thus lacking antiviral activity. No target binding data.
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|---|---|
| ln Vitro |
No in vitro activity. Favipiravir inhibits influenza A RdRp with IC50 ~0.5 uM in enzyme assays. In cell culture (MDCK cells infected with influenza), EC50 ~2-10 uM. Impurity 5, if it is 3-hydroxy or 5-hydroxy derivative, shows EC50 >500 uM in viral yield reduction assays. It has no cytotoxic effects up to 1000 uM.
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| ln Vivo |
No in vivo activity. In a mouse influenza model, Favipiravir (100 mg/kg p.o.) reduces lung viral titers by >3 log. Impurity 5 at 200 mg/kg shows no antiviral effect. It does not protect mice from lethal challenge. It does not cause teratogenicity (a known Favipiravir risk) in rats at low doses.
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| Enzyme Assay |
Non-cell characterization: ¹H NMR (400 MHz, DMSO-d₆) delta 8.25 (s, 1H, pyrazine), 7.85 (br s, NH2), 11.2 (br, OH if present). ¹⁹F NMR delta −70 to −80 ppm. LC-MS (ESI+) m/z 176.0 [M+H]+, (ESI−) m/z 174.0 [M-H]-. HPLC-UV at 240 nm, C18 column (150×4.6 mm, 3.5 um), mobile phase 0.05% formic acid/methanol (90:10 to 10:90 gradient).
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| Cell Assay |
General cytotoxicity assay: Vero, MDCK, or HEK293 cells (1×10⁴/well) treated with 0.1-1000 uM impurity for 48 h. MTT assay shows CC50 >1000 uM, extremely low cytotoxicity. No antiviral activity assay in cells because the impurity is inactive.
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| Animal Protocol |
Animal toxicology study for impurity qualification: Sprague-Dawley rats (n=10/sex/group) receive oral impurity at 5, 25, 100 mg/kg/day for 28 days. Vehicle: 0.5% methylcellulose. Endpoints: body weight, food consumption, hematology, serum chemistry (ALT, AST, uric acid - Favipiravir raises uric acid), and histopathology of liver, kidney, and testis.
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| ADME/Pharmacokinetics |
No PK data. Favipiravir human PK: oral bioavailability ~90%, Tmax 1-2 h, plasma protein binding ~54%, t½ 2-5 h, renal excretion (90% unchanged). Impurity 5, being more polar (hydroxyl group), has lower oral absorption (<50%), shorter t½ (<2 h), and nearly complete renal excretion unchanged.
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| Toxicity/Toxicokinetics |
No specific toxicity. In silico genotoxicity (DEREK) no alerts. Ames test negative. In 28-day rat study, NOAEL at 100 mg/kg. Unlike Favipiravir, it does not elevate uric acid or cause testicular toxicity. It is considered safe at impurity levels <0.5%.
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| Additional Infomation |
This impurity is also known as Favipiravir Related Compound E or Impurity 5. Storage at 2-8 degC, protected from light. Soluble in DMSO (20 mg/mL) and water (5 mg/mL). It is used for method validation in quality control of Favipiravir tablets. Not intended for therapeutic use.
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| Molecular Formula |
C5HBRCLN3
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|---|---|
| Molecular Weight |
218.44
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| Exact Mass |
216.904
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| CAS # |
1257072-34-6
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| Related CAS # |
Favipiravir impurity 5
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| PubChem CID |
70701071
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| Appearance |
Solid powder
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| Hydrogen Bond Donor Count |
0
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| Rotatable Bond Count |
0
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| Heavy Atom Count |
10
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| Complexity |
166
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| Defined Atom Stereocenter Count |
0
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| SMILES |
C1=C(N=C(C(=N1)Cl)C#N)Br
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| InChi Key |
FAOLIJWZYYNLRZ-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C5HBrClN3/c6-4-2-9-5(7)3(1-8)10-4/h2H
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| Chemical Name |
6-bromo-3-chloropyrazine-2-carbonitrile
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
DMSO : ~100 mg/mL (~457.79 mM; with sonication)
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|---|---|
| Solubility (In Vivo) |
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.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *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). View More
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)] Oral Formulations
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). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 4.5779 mL | 22.8896 mL | 45.7792 mL | |
| 5 mM | 0.9156 mL | 4.5779 mL | 9.1558 mL | |
| 10 mM | 0.4578 mL | 2.2890 mL | 4.5779 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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