When LPS-stimulated microglia were treated with 5, 10, and 20 μM Ribavirin GMP (ICN-1229), the levels of NO2 were reduced by 43% (p<0.05), 53% (p<0.05), and 59% (p<0.05). In non-stimulated cultures, ribavirin GMP (ICN-1229) (10 mM) did not significantly reduce cell surface area; however, in LPS-stimulated microglia, it did considerably reduce cell surface area (32%, p<0.05) [3]. Combining ribavirin GMP (ICN-1229) with CM-10-18 decreases viral replication, and ribavirin GMP (ICN-1229) is active against DENV with an EC50 of 3 μM in A549 cells [4]. Hepatitis C virus (HCV) replication is inhibited in functional hepatocyte-like cells derived from human iPSC cells by ribavirin (20 μM) when given for seven days [6]. By controlling genes related to apoptosis regulation, ribavirin (1, 10, 25 μg/mL, 72 hours) reduces ZILV-induced apoptosis in hNPCs and enhances survival signaling via the PI3K/AKT pathway [7]. qPCR in real time[7]

JAT, in combination with interferon and ribavirin GMP (ICN-1229), dramatically decreased (p<0.01) ALT, AST activity, and bilirubin levels. JAT, Interferon, or Ribavirin GMP When administered in isolation with CCl4, Coral seems to have some hepatoprotective effects on CCl4, as shown by the absence of grains, extremely poor feeding, and normal liver cords. TGF-β and Bax expression was decreased in groups treated with JAT, polystirrin, and ribavirin GMP (ICN-1229), either separately or in combination. The triple treatment group receiving interferon, ribavirin GMP (ICN-1229), and JAT experienced a substantial decrease in p53 expression [1]. At the serum and umbilical cord levels, wistar treated with 400 mg of ribavirin GMP (ICN-1229) capsules had a considerable drop in activin A and a large increase in follistatin. Ribavirin GMP (ICN-1229): In mice, ribavirin GMP (40 mg/kg, po) only greatly elevated CM-10 in conjunction with IFN-α or Peg-IFN-α, which had an antiviral effectiveness of -18. In cultured cells, ribavirin GMP (ICN-1229) decreases antiviral activity [2]. DENV virus infection, while treatment with a single medication can lessen viral alarm [4].

Real Time qPCR[7]
Cell Types: hNPCs
Tested Concentrations: 1, 10, 25 μg/ml
Incubation Duration: 72 h
Experimental Results: Increased BCL2 mRNA levels and diminished BAX mRNA levels compared with DMSO control-treated cells.

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Western Blot Analysis[7]
Cell Types: hNPC
Tested Concentrations: 1, 10, 25 μg/ml
Incubation Duration: 72 hrs (hours)
Experimental Results: AKT phosphorylation increased compared to control-treated ZIKV-infected cells.

Absorption, Distribution and Excretion
Ribavirin is reported to be rapidly and extensively absorbed after oral administration. After an oral dose of 1200 mg ribavirin, peak plasma concentration (Cmax) is reached in an average of 2 hours. The oral bioavailability of 600 mg ribavirin is 64%. Ribavirin metabolites are excreted via the kidneys. After an oral dose of 600 mg of radiolabeled ribavirin, approximately 61% of the drug is detected in urine and 12% in feces. 17% of the administered dose is excreted unchanged. Ribavirin has a large volume of distribution. The total apparent clearance after a single oral dose of 1200 mg ribavirin is 26 L/h. Ribavirin is systemically absorbed via the respiratory tract after nasal and oral inhalation. The bioavailability of ribavirin administered via nasal and oral inhalation has not been determined but may depend on the nebulization method (e.g., oxygen mask, face mask, oxygen tent). At a constant flow rate, the theoretical amount of drug reaching the respiratory tract is directly related to the concentration of the nebulized drug solution and the duration of inhalation therapy. Furthermore, changes in the aerosol delivery method can also affect the amount of drug reaching the respiratory tract. When using a small-particle aerosol generator for oral and nasal inhalation of a 190 μg/L nebulized ribavirin solution, the estimated average proportion of the inhaled dose deposited in the respiratory tract is approximately 70%, but the actual deposition depends on various factors, including respiratory rate and tidal volume. When using a small-particle aerosol generator for oral and nasal inhalation, peak plasma ribavirin concentrations typically occur at the end of inhalation and increase with prolonged inhalation time. In a small number of pediatric patients, after 3 consecutive days of nasal and oral inhalation at a dose of 0.82 mg/kg/hr via face mask for 2.5 hours, the average peak plasma ribavirin concentration was 0.19 μg/mL (range: 0.11–0.388 μg/mL). In a small number of patients, peak plasma ribavirin concentrations were 0.275 μg/mL (range: 0.21–0.35 μg/mL) or 1.1 μg/mL (range: 0.45–2.18 μg/mL) when administered via 0.82 mg/kg/hour for 5 hours daily via mask, nebulizer tent, or respirator for 20 hours daily. Peak plasma ribavirin concentrations were 1.7 μg/mL (range: 0.38–3.58 μg/mL) when administered via endotracheal inhaler with a given dose of ribavirin. …Peak plasma concentrations of commonly administered ribavirin via nasal and oral inhalation were lower than those reported to reduce respiratory syncytial virus plaque formation by 85–98%.
After patients inhale ribavirin via nasal and oral routes, the concentration of ribavirin in respiratory secretions may be significantly higher than the plasma concentration. In a small number of pediatric patients who received ribavirin via nasal and oral routes for 8 hours daily for 3 consecutive days at a dose of 0.82 mg/kg/hour, the peak drug concentration in respiratory secretions (from endotracheal intubation) ranged from 250 to 1925 μg/mL. In pediatric patients receiving ribavirin via nasal and oral routes for 5 consecutive days for 20 hours daily at a dose of 0.82 mg/kg/hour, the concentration of ribavirin in respiratory secretions (from endotracheal intubation) during treatment ranged from 313 to 28,250 μg/mL, with a mean peak concentration of 3075 μg/mL at the end of treatment (range: 313–7050 μg/mL). The concentrations of ribavirin achieved through nasal and oral inhalation in respiratory secretions may be significantly higher than the concentrations required in vitro to inhibit plaque formation by susceptible strains of respiratory syncytial virus (RSV). However, because RSV exists within cells infected by the respiratory virus, the manufacturer notes that intracellular respiratory drug concentrations are likely more closely related to plasma ribavirin concentrations than to concentrations measured in respiratory secretions. Oral ribavirin is rapidly absorbed, reaching peak plasma concentrations within 1–3 hours after multiple doses. However, due to first-pass metabolism, the absolute bioavailability of oral ribavirin is only about 64% on average. For more complete data on absorption, distribution, and excretion of ribavirin (10 items in total), please visit the HSDB record page. Metabolism/Metabolites: First, and essential for activation, ribavirin is phosphorylated intracellularly by adenosine kinase to produce ribavirin monophosphate, diphosphate, and triphosphate metabolites. After ribavirin is activated and exerts its effect, it undergoes two metabolic pathways: reversible phosphorylation or degradation via deribosylation and amide hydrolysis to produce the triazole carboxylic acid metabolite. In vitro studies have shown that ribavirin is not a substrate of CYP450 enzymes. Ribavirin is primarily metabolized to deribosylated ribavirin (1,2,4-triazole-3-carboxamide), which may occur in the liver; 1,2,4-triazole-3-carboxamide has been reported to have similar antiviral activity against various RNA and DNA viruses as ribavirin. The drug is also metabolized to 1,2,4-triazole-3-carboxylic acid. In vitro studies have shown that ribavirin is primarily phosphorylated intracellularly via adenosine kinase and other cellular enzymes, metabolizing to ribavirin-5'-monophosphate, 5'-diphosphate, and 5'-triphosphate. In vivo phosphorylation is likely a necessary condition for the drug to exert its antiviral activity. Ribavirin is also phosphorylated within erythrocytes, primarily to produce ribavirin-5'-triphosphate. Of the drugs metabolized within erythrocytes, approximately 81%, 16%, and 3% exist as ribavirin-5'-triphosphate, diphosphate, and monophosphate, respectively. Studies have shown that the prolonged distribution of the drug within erythrocytes may be due to the low activity of phosphatases in these cells, and drug transport from cells depends on dephosphorylation by phosphatases. Ribavirin undergoes two metabolic pathways: (i) a reversible phosphorylation pathway occurring in nucleated cells; and (ii) a degradation pathway involving deribosylation and amide hydrolysis, producing triazole carboxylic acid metabolites. Ribavirin, along with its triazole carboxylic acid metabolites, is excreted via the kidneys.
Biological Half-Life
Following a single oral dose of 1200 mg ribavirin, the terminal half-life is approximately 120 to 170 hours.
Distribution: Intravenous injection: approximately 0.2 hours. Elimination: Inhalation: 9.5 hours. Intravenous and oral (single dose): 0.5 to 2 hours. In erythrocytes: 40 days. Terminal half-life: Intravenous and oral: Single dose: 27 to 36 hours. Single oral tablet: 120 to 170 hours. Steady state: Approximately 151 hours. Mean: Multiple oral administration, capsules: 298 hours. Based on limited data, it has been reported that the half-life of ribavirin in respiratory secretions is approximately 1.4–2.5 hours after 3 days of nasal and oral inhalation. In a small number of pediatric patients, the mean plasma half-life of ribavirin after nasal and oral inhalation is approximately 9.5 hours (range: 6.5–11 hours). In a small number of healthy adults, plasma ribavirin concentrations show a multiphasic decline after a single oral dose, with a mean half-life of 24 hours 10–80 hours post-dose and a terminal half-life of 48 hours or longer.

Interactions
Ribavirin's in vitro and in vivo antiviral activity against certain viruses (e.g., influenza virus) may be enhanced by other antiviral drugs (e.g., amantadine, ribavirin). Ribavirin may antagonize the in vitro antiviral activity of stavudine and zidovudine against HIV; concomitant use of ribavirin with these two drugs should be avoided. Oral ribavirin is not recommended for use with dipanosin. Cases of fatal liver failure, peripheral neuropathy, pancreatitis, and symptomatic hyperlactatemia/lactal acidosis have been reported in clinical trials. In vitro studies have shown that ribavirin enhances the antiretroviral activity of dipanosin against human immunodeficiency virus (HIV; formerly known as HTLV-III/LAV) and Moroni murine sarcoma virus. Conversely, in vitro studies have shown that ribavirin antagonizes the antiviral activity of zidovudine and zalcitabine against HIV. Ribavirin appears to enhance the antiretroviral activity of didanoxin by promoting the production of didanoxin-S'-triphosphate (the metabolically active metabolite of didanoxin with antiviral activity). The mechanism by which ribavirin antagonizes the antiretroviral activity of zidovudine or zalcitabine is not fully elucidated, but studies suggest that ribavirin may interfere with the phosphorylation steps that convert the drug into its active triphosphate metabolites (deoxythymidine triphosphate and dideoxycytidine-S'-triphosphate, respectively).

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Non-human toxicity values
Oral LD50 in rats: 5.3 g/kg
Oral LD50 in mice: 2 g/kg
Intraperitoneal LD50 in mice: 0.9-1.3 g/kg
Intraperitoneal LD50 in rats: 2 g/kg

[1]. Robert O Baker, et al. Potential antiviral therapeutics for smallpox, monkeypox and other orthopoxvirus infections. Antiviral Res. 2003 Jan;57(1-2):13-23.
[2]. Abdel-Hamid NM, et al. Synergistic Effects of Jerusalem Artichoke in Combination with Pegylated Interferon Alfa-2a and Ribavirin Against Hepatic Fibrosis in Rats. Asian Pac J Cancer Prev. 2016;17(4):1979-85.
[3]. Refaat B, et al. The effects of pegylated interferon-α and ribavirin on liver and serum concentrations of activin-A and follistatin in normal Wistar rat: a preliminary report. BMC Res Notes. 2015 Jun 26;8:265
[4]. Savic D, et al. Ribavirin shows immunomodulatory effects on activated microglia. Immunopharmacol Immunotoxicol. 2014 Dec;36(6):433-41
[5]. Chang J, et al. Combination of α-glucosidase inhibitor and ribavirin for the treatment of dengue virus infection in vitro and in vivo. Antiviral Res. 2011 Jan;89(1):26-34
[6]. Sa-Ngiamsuntorn K, et al. A robust model of natural hepatitis C infection using hepatocyte-like cells derived from human induced pluripotent stem cells as a long-term host. Virol J. 2016 Apr 5;13:59.
[7]. Kim JA, Seong RK, Kumar M, Shin OS. Favipiravir and Ribavirin Inhibit Replication of Asian and African Strains of Zika Virus in Different Cell Models. Viruses. 2018 Feb 9;10(2):72.

Therapeutic Uses

Antimetabolite; Antiviral Drug
Anviral Drug
Ribavirin is used orally and intravenously to treat Lassa fever and as a post-exposure prophylaxis for high-risk contacts. It may also be equally effective against other viral hemorrhagic fevers, including hemorrhagic fever with renal syndrome, Crimean-Congo hemorrhagic fever, and Rift Valley fever. /Not included in the U.S. product label/
Ribavirin inhalation solution is used as adjunctive therapy for the treatment of influenza A and B in young adults, especially when treatment is initiated early in the illness (e.g., within 24 hours of the onset of initial symptoms). /Not included in the U.S. product label/
Ribavirin inhalation solution is used to treat severe lower respiratory tract infections (including bronchiolitis and pneumonia) caused by respiratory syncytial virus (RSV) in hospitalized infants and young children, especially those at risk of severe or complicated RSV infection; such populations include premature infants and infants with structural or physiological cardiopulmonary disease, bronchopulmonary dysplasia, immunodeficiency, or impending respiratory failure. Ribavirin is indicated for the treatment of RSV infection in infants requiring mechanical ventilation. /Included in the US product label/

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Drug Warnings
FDA Pregnancy Risk Category: X /Contraindicated during pregnancy. Animal or human studies, as well as investigational or post-marketing reports, have demonstrated that the risk of fetal malformation or abnormalities significantly outweighs any potential benefit to the patient. /
When deciding whether to treat pediatric patients, evidence of disease progression, such as liver inflammation and fibrosis, as well as prognostic factors, HCV genotype, and viral load should be considered. The treatment benefit should be weighed against the safety outcomes observed in pediatric patients in clinical trials.
Sudden deterioration of respiratory function can sometimes occur in infants receiving ribavirin inhalation (including those with respiratory syncytial virus infection) or adults with chronic obstructive pulmonary disease (COPD) or asthma. In infants with underlying life-threatening conditions, inhalation of this drug has been associated with worsening and deterioration of respiratory function, apnea, and dependence on assisted ventilation. In adults with chronic obstructive pulmonary disease (COPD) or asthma, ribavirin treatment is often accompanied by worsening lung function, with some asthmatic adults experiencing dyspnea and chest pain. Mild lung function abnormalities have also been observed in healthy adults after inhaling ribavirin. Bronchospasm, pulmonary edema, hypoventilation, cyanosis, dyspnea, bacterial pneumonia, pneumothorax, apnea, atelectasis, and ventilator dependence have also been associated with ribavirin inhalation therapy. Some infants have experienced bronchospasm-induced respiratory deterioration during ribavirin treatment, and these deaths have been determined by the treating physician to be possibly related to ribavirin inhalation therapy. Patients receiving ribavirin inhalation therapy may also experience rash, eyelid erythema, and conjunctivitis. These symptoms usually subside within hours of discontinuing ribavirin. In addition, hearing impairment (e.g., hearing loss, tinnitus), dizziness, hypertriglyceridemia, and fatal and non-fatal pancreatitis have been observed in patients receiving ribavirin in combination with interferon alpha-2b. For more complete data on ribavirin (23 in total), please visit the HSDB records page.

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Pharmacodynamics
Ribavirin exerts direct antiviral activity against a variety of DNA and RNA viruses by increasing the mutation frequency of the genomes of various RNA viruses. It belongs to the nucleoside antimetabolite class of drugs and interferes with the replication of viral genetic material. Due to its structural similarity to the building blocks of RNA molecules, this drug inhibits the activity of RNA-dependent RNA polymerase.

C8H12N4O5

244.2047

244.08

36791-04-5

Ribavirin;36791-04-5

37542

White to off-white solid powder

2.1±0.1 g/cm3

639.8±65.0 °C at 760 mmHg

174-176°C

340.7±34.3 °C

0.0±2.0 mmHg at 25°C

1.823

-2.26

4

7

3

17

304

4

C1=NC(=NN1[C@H]2[C@@H]([C@@H]([C@H](O2)CO)O)O)C(=O)N

IWUCXVSUMQZMFG-AFCXAGJDSA-N

InChI=1S/C8H12N4O5/c9-6(16)7-10-2-12(11-7)8-5(15)4(14)3(1-13)17-8/h2-5,8,13-15H,1H2,(H2,9,16)/t3-,4-,5-,8-/m1/s1

1-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-1,2,4-triazole-3-carboxamide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

H2O : ~100 mg/mL (~409.50 mM)
DMSO : ~100 mg/mL (~409.50 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.)