Combining PSI-7976 and PSI-7977, two diastereoisomers that are known to be a more potent inhibitor of HCV RNA replication in HCV replicon tests, results in PSI-7851. PSI-7976 is hydrolyzed more favorably by carboxylesterase 1 (CES1) than PSI-7977. Additionally, PSI-7976 is a more effective substrate for CES1 than cathepsin A (CatA) according to kinetic data[1].

Toxicity Summary
IDENTIFICATION AND USE: Sofosbuvir is a white to off-white crystalline solid. Sofosbuvir is a direct-acting antiviral agent (pan-genotypic polymerase inhibitor) against the hepatitis C virus. It is used in conjunction with other antiviral agents for the treatment of chronic hepatitis C virus (HCV) genotype 1, 2, 3, or 4 infections in adults, including those with hepatocellular carcinoma awaiting liver transplantation and those with human immunodeficiency virus (HIV) co-infection. Sofosbuvir must be used as part of a multiple-drug regimen and should not be used alone for the treatment of chronic HCV infection. HUMAN EXPOSURE AND TOXICITY: The highest documented dose of sofosbuvir was a single supratherapeutic dose of sofosbuvir 1200 mg administered to 59 healthy subjects. There were no untoward effects observed at this dose level, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups. Sofosbuvir did not induce chromosome aberration using human peripheral blood lymphocytes. ANIMAL STUDIES: Single dose toxicity study was performed with GS-9851/PSI-7851 (the diastereomeric mixture) in rats. No mortality, clinical signs, body weight changes, macroscopic pathology, or organ weight changes for liver and kidney up to a highest dose of 1,800 mg/kg. Sofosbuvir or GS-9851, a 1:1 diastereomeric mixture of sofosbuvir and its stereoisomer, were evaluated in repeat-dose oral toxicity studies up to 13 weeks in mice, 26 weeks in rats, and 39 weeks in dogs. The primary target organs identified were the cardiovascular, hepatobiliary, gastrointestinal (GI) and hematopoietic (erythroid) systems. In the 7-day toxicity studies with GS-9851 doses of 2000 mg/kg/day in the rat and 1500 mg/kg/day in the dog resulted (but were not limited to) in increased mucus secretions in the stomach, glycogen depletion, and increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin, with associated histopathologic liver findings in dogs; and heart adverse effects in rats (e.g., multifocal cardiac myofiber degeneration) and dogs (e.g., increased QT/QTc intervals). Findings in the liver and heart were not observed in long-term studies with GS-9851 or sofosbuvir. In chronic toxicity studies in rats (26 weeks) and dogs (39 weeks), effects included (but were not limited to) GI-related clinical signs (e.g., soft feces and emesis) and a decrease (e.g., approximately 10%) in mean red cell indices that were observed mainly in the high-dose group of dogs. Sofosbuvir had no effects on embryo-fetal viability or on fertility when evaluated in rats. No teratogenic effects were observed in rat and rabbit developmental toxicity studies with sofosbuvir. It had no adverse effects on behavior, reproduction, or development of the offspring in the rat pre- and post-natal development study. At the highest dose tested, exposure to the predominant circulating metabolite GS-331007 was at least 8-fold the exposure in humans at the recommended clinical dose. Fertility was normal in the offspring of rats exposed daily from before birth (in utero) through lactation day 20 at daily GS-331007 exposures (AUC) of approximately 12-fold higher than human exposures at the recommended clinical dose. Two-year carcinogenicity studies in mice and rats were conducted with sofosbuvir. Mice were administered doses of up to 200 mg/kg/day in males and 600 mg/kg/day in females, while rats were administered doses of up to 750 mg/kg/day in males and females. No increase in the incidence of drug-related neoplasms were observed at the highest doses tested in mice and rats, resulting in AUC exposure to the predominant circulating metabolite GS-331007 of approximately 7- and 30-fold (in mice) and 13- and 17-fold (in rats), in males and females respectively, the exposure in humans at the recommended clinical dose. Sofosbuvir was not genotoxic in a battery of in vitro or in vivo assays, including bacterial mutagenicity, and in vivo mouse micronucleus assays.

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Interactions
Concomitant use of rifampin, a potent inducer of P-gp in the intestine, and sofosbuvir may cause decreased plasma concentrations of sofosbuvir and GS-331007 and may lead to decreased therapeutic effect of sofosbuvir. Rifampin and sofosbuvir should not be used concomitantly.
Rifabutin is expected to cause decreased plasma concentrations of sofosbuvir and GS-331007, which may lead to decreased therapeutic effect of sofosbuvir. Concomitant use of rifabutin and sofosbuvir is not recommended.
When used concomitantly with sofosbuvir, certain anticonvulsants (i.e., carbamazepine, oxcarbazepine, phenobarbital, phenytoin) are expected to decrease plasma concentrations of sofosbuvir and GS-331007, which may lead to decreased therapeutic effect of sofosbuvir. Concomitant use of these anticonvulsants and sofosbuvir is not recommended.
Sofosbuvir is a substrate of breast cancer resistance protein (BCRP); GS-331007 is not a BCRP substrate. Inhibitors of BCRP may cause increased plasma concentrations of sofosbuvir without increasing plasma concentrations of GS-331007. Sofosbuvir and GS-331007 are not BCRP inhibitors; pharmacokinetic interactions are unlikely with drugs that are BCRP substrates.
For more Interactions (Complete) data for Sofosbuvir (13 total), please visit the HSDB record page.

[1]. Mechanism of activation of PSI-7851 and its diastereoisomer PSI-7977. J Biol Chem. 2010 Nov 5;285(45):34337-47.

Therapeutic Uses
Sovaldi is a hepatitis C virus (HCV) nucleotide analog NS5B polymerase inhibitor indicated for the treatment of chronic hepatitis C (CHC) infection as a component of a combination antiviral treatment regimen. /Included in US product label/
The following points should be considered when initiating treatment with Sovaldi: Monotherapy of Sovaldi is not recommended for treatment of chronic hepatitis C (CHC). Treatment regimen and duration are dependent on both viral genotype and patient population. Treatment response varies based on baseline host and viral factors.

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Drug Warnings
FDA is warning that serious slowing of the heart rate can occur when the antiarrhythmic drug amiodarone is taken together with either the hepatitis C drug Harvoni (ledipasvir/sofosbuvir) or with Sovaldi (sofosbuvir) taken in combination with another direct acting antiviral for the treatment of hepatitis C infection. FDA is adding information about serious slowing of the heart rate, known as symptomatic bradycardia, to the Harvoni and Sovaldi labels. FDA is recommending that health care professionals should not prescribe either Harvoni or Sovaldi combined with another direct acting antiviral, such as the investigational drug daclatasvir or Olysio (simeprevir), with amiodarone. FDA review of submitted postmarketing adverse event reports found that patients can develop a serious and life-threatening symptomatic bradycardia when either Harvoni or Sovaldi combined with another direct-acting antiviral is taken together with amiodarone. The reports included the death of one patient due to cardiac arrest and three patients requiring placement of a pacemaker to regulate their heart rhythms. The other patients recovered after discontinuing either the hepatitis C drugs or amiodarone, or both. The cause of these events could not be determined. FDA will continue to monitor Harvoni and Sovaldi for risks of serious symptomatic bradycardia and further investigate the reason why the use of amiodarone with these hepatitis C drugs led to the heart-related events.
Concomitant use of sofosbuvir with drugs that are potent inducers of the P-glycoprotein (P-gp) transport system in the intestine (e.g., rifampin, St. John's wort) is not recommended since this may result in substantially decreased sofosbuvir plasma concentrations and could lead to reduced therapeutic effect of sofosbuvir.
Anemia has been reported in patients receiving sofosbuvir in conjunction with ribavirin or in conjunction with peginterferon alfa andribavirin. In clinical trials, anemia was reported in 21% of patients who received 12 weeks of treatment with sofosbuvir, peginterferon alfa, and ribavirin compared with 12% of patients who received 24 weeks of treatment with peginterferon alfa and ribavirin without sofosbuvir. In addition, hemoglobin concentrations less than 10 g/dL were reported in 23% of patients who received 12 weeks of treatment with sofosbuvir, peginterferon alfa, and ribavirin compared with 14% of patients who received 24 weeks of treatment with peginterferon alfa and ribavirin without sofosbuvir.
Adverse effects reported in more than 20% of patients receiving sofosbuvir in conjunction with ribavirin and peginterferon alfa include fatigue, headache, nausea, insomnia, and anemia.
For more Drug Warnings (Complete) data for Sofosbuvir (13 total), please visit the HSDB record page.

C22H29FN3O9P

529.45

529.163

1190308-01-0

Sofosbuvir;1190307-88-0;Sofosbuvir impurity C;1496552-28-3;Sofosbuvir impurity A;1496552-16-9;Sofosbuvir-d6;1868135-06-1;Sofosbuvir-13C,d3

45375809

White to off-white solid powder

2.047

3

11

11

36

913

6

C[C@@H](C(=O)OC(C)C)NP(=O)(OC[C@@H]1[C@H]([C@@]([C@@H](O1)N2C=CC(=O)NC2=O)(C)F)O)OC3=CC=CC=C3

TTZHDVOVKQGIBA-IAAJYNJHSA-N

InChI=1S/C22H29FN3O9P/c1-13(2)33-19(29)14(3)25-36(31,35-15-8-6-5-7-9-15)32-12-16-18(28)22(4,23)20(34-16)26-11-10-17(27)24-21(26)30/h5-11,13-14,16,18,20,28H,12H2,1-4H3,(H,25,31)(H,24,27,30)/t14-,16+,18+,20+,22+,36?/m0/s1

propan-2-yl (2S)-2-[[[(2R,3R,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-4-fluoro-3-hydroxy-4-methyloxolan-2-yl]methoxy-phenoxyphosphoryl]amino]propanoate

psi-7976 psi7976 psi 7976

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.)