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 following oral administration. The average time to reach Cmax was 2 hours after oral administration of 1200 mg ribavirin. The oral bioavailability is 64% following a single oral dose administration of 600mg ribavirin.
The metabolites of ribavirin are renally excreted. After the oral administration of 600mg radiolabeled ribavirin, approximately 61% of the drug was detected in the urine and 12% was detected in the feces. 17% of administered dose was in unchanged form.
Ribavirin displays a large volume of distribution.
The total apparent clearance rate after a single oral dose administration of 1200 mg ribavirin is 26L/h.
Ribavirin is absorbed systemically from the respiratory tract following nasal and oral inhalation. The bioavailability of ribavirin administered via nasal and oral inhalation has not been determined but may depend on the method of drug delivery during nebulization (eg, oxygen hood, face mask, oxygen tent). At a constant flow rate, the amount of drug delivered to the respiratory tract theoretically is directly related to the concentration of nebulized drug solution and the duration of inhalation therapy. In addition, alterations in the method of aerosol delivery can affect the amount of drug reaching the respiratory tract. The fraction of an inhaled dose of ribavirin that is deposited in the respiratory tract during oral and nasal inhalation of a nebulized solution containing 190 ug/L using a small particle aerosol generator has been estimated to average about 70%, but the actual amount deposited depends on several factors including respiratory rate and tidal volume.
Peak plasma ribavirin concentrations generally appear to occur at the end of the inhalation period when the drug is inhaled orally and nasally using a small particle aerosol generator, and increase with increasing duration of the inhalation period. Following nasal and oral inhalation (via face mask) of 0.82 mg/kg/hr for 2.5 hr daily for 3 days in a limited number of pediatric patients, peak plasma ribavirin concentrations averaged 0.19 (range: 0.11-0.388) ug/mL. Peak plasma ribavirin concentrations averaged 0.275 (range: 0.21-0.35) or 1.1 (range: 0.45-2.18) ug/mL in a limited number of patients inhaling 0.82 mg/kg per hour for 5 or 8 hr daily, respectively, for 3 days, and averaged 1.7 (range: 0.38-3.58) ug/mL in a limited number of pediatric patients inhaling 0.82 mg/kg per hour via face mask, mist tent, or respirator for 20 hr daily for 5 days. Highest plasma concentrations for a given dosage of ribavirin appear to be achieved in patients receiving the drug from the aerosol generator via an endotracheal tube. ... Peak plasma ribavirin concentrations achieved with nasal and oral inhalation of usual dosages of the drug are less than concentrations that reportedly reduce respiratory syncytial virus plaque formation by 85-98%.
Concentrations of ribavirin achieved in respiratory tract secretions in patients inhaling the drug nasally and orally are likely to be substantially greater than those achieved in plasma. In a limited number of pediatric patients who received a nasally and orally inhaled ribavirin dose of 0.82 mg/kg per hour for 8 hr daily for 3 days, peak concentrations of the drug in respiratory tract secretions (from endotracheal tube) ranged from 250-1925 ug/mL. In pediatric patients who received 0.82 mg/kg per hour via nasal and oral inhalation for 20 hr daily for 5 days, ribavirin concentrations in respiratory tract secretions (from endotracheal tube) ranged from 313-28,250 ug/mL during therapy, with peak concentrations averaging 3075 (range: 313-7050) ug/mL at the end of therapy. Concentrations of ribavirin achieved in respiratory tract secretions via nasal and oral inhalation are likely to be substantially greater than concentrations necessary to inhibit plaque formation of susceptible strains of respiratory syncytial virus in vitro; however, because respiratory syncytial virus is found within virus infected cells in the respiratory tract, the manufacturer states that intracellular respiratory tract drug concentrations may be more closely related to plasma ribavirin concentrations than to those measured in respiratory tract secretions.
Ribavirin is rapidly absorbed following oral administration, with peak plasma concentrations of the drug occurring within 1-3 hr after multiple doses. However, the absolute bioavailability of ribavirin averages only 64% following oral administration because the drug undergoes first-pass metabolism.
For more Absorption, Distribution and Excretion (Complete) data for RIBAVIRIN (10 total), please visit the HSDB record page.

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Metabolism / Metabolites
First and as a step required for activation, ribavirin is phosphorylated intracellularly by adenosine kinase to ribavirin mono-, di-, and triphosphate metabolites. After activation and function, ribavirin undergoes two metabolic pathways where it is reversibly phosphorlyated or degraded via deribosylation and amide hydrolysis to yield a triazole carboxylic acid metabolite. In vitro studies indicate that ribavirin is not a substrate of CYP450 enzymes.
Ribavirin is metabolized principally to deribosylated ribavirin (the 1,2,4-triazole-3-carboxamide), probably in the liver; the antiviral activity of 1,2,4-triazole-3-carboxamide against various RNA and DNA viruses is reportedly similar to ribavirin. The drug is also metabolized to 1,2,4-triazole-3-carboxylic acid. In vitro, ribavirin has been shown to be metabolized to ribavirin-5'-monophosphate, -diphosphate, and -triphosphate, principally by intracellular phosphorylation of the drug via adenosine kinase and other cellular enzymes. It is likely that phosphorylation in vivo is necessary for the antiviral activity of the drug. Ribavirin also undergoes phosphorylation in erythrocytes, principally to ribavirin-5'-triphosphate; approximately 81, 16, and 3% of drug metabolized in erythrocytes is present as ribavirin-5'-triphosphate, -diphosphate, and -monophosphate, respectively. It has been suggested that prolonged distribution of the drug in erythrocytes may result from minimal phosphatase activity in these cells with transit of the drug out of cells dependent on dephosphorylation via phosphatases.
Ribavirin has two pathways of metabolism: (i) a reversible phosphorylation pathway in nucleated cells; and (ii) a degradative pathway involving deribosylation and amide hydrolysis to yield a triazole carboxylic acid metabolite. Ribavirin and its triazole carboxamide and triazole carboxylic acid metabolites are excreted renally.

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Biological Half-Life
The terminal half-life of ribavirin following administration of a single oral dose of 1200 mg is about 120 to 170 hours.
Distribution: Intravenous: Approximately 0.2 hours. Elimination: inhalation: 9.5 hours. Intravenous and oral (single dose): 0.5 to 2 hours. In erythrocytes: 40 days. Terminal: Intravenous and oral: Single dose: 27 to 36 hours. Single oral dose tablet: 120 to 170 hours. Steady state: Approximately 151 hours. Mean :multiple oral dosing, capsule: 298 hours.
Based on limited data, the half-life of ribavirin in respiratory tract secretions following nasal and oral inhalation for 3 days reportedly is approximately 1.4-2.5 hr.
Following nasal and oral inhalation in a limited number of pediatric patients, the plasma half-life of ribavirin averaged about 9.5 (range: 6.5-11) hr. Following oral administration of a single dose of the drug in a limited number of healthy adults, plasma ribavirin concentrations declined in a multiphasic manner, with half-lives averaging 24 hr 10-80 hr after the dose and 48 hr or longer in the terminal phase.

Interactions
In vitro and in vivo antiviral activity of ribavirin against some viruses (eg, influenza virus) may be enhanced by other antiviral agents (eg, amantadine, rimantadine).
Ribavirin may antagonize the in vitro antiviral activity of stavudine and zidovudine against HIV; concomitant use of ribavirin with either of these drugs should be avoided.
Coadministration /of didanosine/ with oral ribavirin is not recommended; cases of fatal hepatic failure, peripheral neuropathy, pancreatitis, and symptomatic hyperlactatemia/lactic acidosis have been reported in clinical trials.
Results of in vitro tests in various cell cultures and peripheral blood lymphocytes indicate that ribavirin may potentiate the antiretroviral activity of didanosine against human immunodeficiency virus (HIV; formerly HTLV-III/LAV) and Moloney murine sarcoma virus. Conversely, results of in vitro tests indicate that ribavirin antagonizes the antiviral activity of zidovudine and zalcitabine against HIV. Ribavirin appears to potentiate the antiretroviral effects of didanosine by promoting formation of didanosine-S'-triphosphate, the metabolically active metabolite of didanosine with antiviral activity. The mechanism by which ribavirin antagonizes the antiretroviral effects of zidovudine or zalcitabine has not been elucidated to date but it has been suggested that ribavirin may interfere with phosphorylation steps that convert the drugs to their active triphosphate metabolites, deoxythymidine triphosphate or dideoxycytidine-S'-triphosphate, respectively.

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Non-Human Toxicity Values
LD50 Rat oral 5.3 g/kg
LD50 Mouse oral 2 g/kg
LD50 Mouse ip 0.9-1.3 g/kg
LD50 Rat ip 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
Antimetabolites; Antiviral Agents
Antiviral
Oral and intravenous ribavirin are used in the treatment of Lassa fever and as post-exposure prophylaxis in contacts at hgh risk. It may be similarly effective with other viral hemorrhagic fevers, including hemorrhagic fever with renal syndrome, Crimean-Congo hemorrhagic fever, and Rift Valley fever. /NOT included in US product labeling/
Ribavirin inhalation solution is used as a secondary agent in the treatment of influenza A and B in young adults when treatment is started early (eg, within 24 hours of initial symptoms) in the course of the disease. /NOT included in US product labeling/
Ribavirin inhalation solution is for the treatment of severe lower respiratory tract infections (including bronchiolitis and pneumonia) caused by respiratory syncytial virus (RSV) in hospitalized infants and young children who are at high risk for severe or complicated RSV infection; this category includes premature infants and infants with structural or physiologic cardiopulmonary disorder, bronchopulmonary dysplasia, immunodeficiency, or imminent respiratory failure. Ribavirin is indicated in the treatment of RSV infections in infants requiring mechanical ventilator assistance. /Included in US product labeling/

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Drug Warnings
FDA Pregnancy Risk Category: X /CONTRAINDICATED IN PREGNANCY. Studies in animals or humans, or investigational or post-marketing reports, have demonstrated positive evidence of fetal abnormalities or risk which clearly outweights any possible benefit to the patient./
Evidence of disease progression, such as hepatic inflammation and fibrosis, as well as prognostic factors for response. HCV genotype and viral load, should be considered when deciding to treat a pediatric patient. The benefits of treatment should be weighed against the safety findings observed for pediatric patients in clinical trials.
Worsening of respiratory function has occurred, sometimes suddenly, during ribavirin inhalation therapy in infants with RSV infections or in adults with chronic obstructive pulmonary disease (COPD) or asthma. In infants with underlying life-threatening conditions, inhalation of the drug has been associated with aggravation and worsening of respiratory function, apnea, and physical dependence on assisted respiration. In adults with COPD or asthma, therapy with the drug frequently has been associated with deterioration in pulmonary function, and dyspnea and chest soreness have occurred in several adults with asthma. Minor pulmonary function abnormalities have also been observed in healthy adults receiving ribavirin inhalation. Bronchospasm, pulmonary edema, hypoventilation, cyanosis, dyspnea, bacterial pneumonia, pneumothorax, apnea, atelectasis, and ventilator dependence also have been associated with ribavirin inhalation therapy. Several deaths that were characterized as possibly related to ribavirin inhalation therapy by the treating physician occurred in infants who experienced worsening respiratory status related to bronchospasm while receiving the drug.
Rash, erythema of the eyelids, and conjunctivitis have occurred in patients receiving ribavirin inhalation therapy. These effects usually resolve within hours after ribavirin therapy is discontinued. In addition, hearing disorders (e.g., hearing loss, tinnitus), vertigo, hypertriglyceridemia, and fatal and nonfatal pancreatitis have been observed in patients receiving ribavirin in conjunction with interferon alfa-2b.
For more Drug Warnings (Complete) data for RIBAVIRIN (23 total), please visit the HSDB record page.

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Pharmacodynamics
Ribavirin mediates direct antiviral activity against a number of DNA and RNA viruses by increasing the mutation frequency in the genomes of several RNA viruses. It is a member of the nucleoside antimetabolite drugs that interfere with duplication of the viral genetic material. The drug inhibits the activity of the enzyme RNA dependent RNA polymerase, due to its resemblence to building blocks of the RNA molecules.

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.)