Evaluation of the genetic toxicity of sofosbuvir and simeprevir with and without ribavirin in a human-derived liver cell line.

Direct-acting antivirals have revolutionized the treatment of chronic hepatitis C. Sofosbuvir and simeprevir are prescribed worldwide. However, there is a scarcity of information regarding their genotoxicity. Therefore, the present study assessed the cytotoxic and genotoxic effects of sofosbuvir and simeprevir, alone and combined with ribavirin. HepG2 cells were analyzed using the in vitro cytokinesis-block micronucleus cytome assay. Cells were treated for 24 h with sofosbuvir (0.011-1.511 mM), simeprevir (0.156-5.0 µM), and their combinations with ribavirin (0.250-4.0 mM). No significant differences were observed in the nuclear division cytotoxicity index, reflecting the absence of cytotoxic effects associated to sofosbuvir. However, the highest concentration of simeprevir showed a significant difference for the nuclear division cytotoxicity index. Moreover, significant results were observed for nuclear division cytotoxicity index in two combinations of sofosbuvir plus ribavirin and only in the highest combination of simeprevir plus ribavirin. Additionally, our results showed that sofosbuvir did not increase the frequency of chromosomal damage, but simeprevir significantly increased the frequency of micronuclei at the highest concentrations. The combination index demonstrated that both sofosbuvir and simeprevir produced antagonism to the genotoxic effects of ribavirin. In conclusion, our results showed that simeprevir, but not sofosbuvir, has genotoxic effects in HepG2 cells.

Histological and biochemical studies on effect of Sofosbuvir (Sovaldi) on adult male albino rat kidney.

Sofosbuvir (sovaldi) is the backbone of many anti-HCV drugs. We aimed to demonstrate the effect of sofosbuvir on the adult male albino rat kidney. Sixty adult male albino rats were used. The animals were divided equally into 2 main groups (I and II), and each group was divided equally into 3 subgroups (A, B, and C). In group I (control group), each rat was gavaged 0.5 ml distilled water daily for 4 weeks. In group II (sofosbuvir treated group), each albino rat was gavaged 0.5 ml distilled water containing 7.2 mg sofosbuvir daily for 4 weeks. The rats were sacrificed at the end of the 4th week (subgroups IA and IIA), 6th week (subgroups IB and IIB), and 8th week (subgroups IC and IIC) from the start of the treatment. The kidneys were used for histological study while blood samples were used for biochemical study. The obtained data were statistically analyzed. Sofosbuvir (sovaldi) induced pathological changes that gave the criteria of acute Kidney injury in the adult male albino rats. The pathological changes were confirmed by elevation of serum level of urea and creatinine. After 2 and 4 weeks of drug withdrawal, the kidney incompletely recovered. We concluded that sofosbuvir induced criteria of acute tubular injury in the kidney of the adult male albino rats. This renal injury was proved by histological and biochemical studies. These insults were incompletely reversible after the end the treatment.

Amino-decorated mesoporous silica nanoparticles for controlled sofosbuvir delivery.

The present study describes synthesis of amino-decorated mesoporous silica nanoparticles (MSNs) for sustained delivery and enhanced bioavailability of sofosbuvir. Sofosbuvir is active against hepatitis C virus and pharmaceutically classified as class III drug according to biopharmaceutics classification system (BCS). MSNs were synthesized using modified sol-gel method and the surface was decorated with amino functionalization. Drug loaded MSNs were also grafted with polyvinyl alcohol in order to compare it with the amino-decorated MSNs for sustained drug release. The prepared MSNs were extensively characterized and the optimized formulation was toxicologically and pharmacokinetically evaluated. The functionalized MSNs of 196 nm size entrapped 29.13% sofosbuvir in the pores, which was also confirmed by the decrease in surface area, pore volume and pore size. The drug-loaded amino-decorated MSNs revealed an improved thermal stability as confirmed by thermal analysis. Amino-decorated MSNs exhibited Fickian diffusion controlled sofosbuvir release as compared with non-functionalized and PVA grafted MSNs. Amino-decorated MSNs were deemed safe to use in Sprague-Dawley rats after 14-days exposure as confirmed by the toxicological studies. More interestingly, we achieved a 2-fold higher bioavailability of sofosbuvir in Sprague-Dawley rats in comparison with sofosbuvir alone, and the Tmax was delayed 3-times indicating a sustained release of sofosbuvir.

Evaluation of testicular cytotoxicity and genotoxicity of sofosbuvir and sofosbuvir - ribavirin in the adult male albino rats

Hepatitis C is a widely distributed problem all over the world, especially Egypt. Chronically infected people develop serious liver disease and now it is the most common cause for liver transplantation. Recently, a new regimen, sofosbuvir (sovaldi), alone or with combinations as sovaldi-ribavirin, was approved for treating this disease. There are limited studies that explore the effects of these drugs on the reproductive organs, and hence affection of male fertility while using these drugs. This study aims to throw more light on whether sovaldi or sovaldi-ribavirin causes testicular damaging effects in the adult male albino rats. We investigated the effect of this regimen in a dose equivalent to that used in the human (41 mg/kg once daily orally for sovaldi and 41 mg/kg twice daily orally for ribavirin) for consecutive 5 and 10 days. There was highly significant decrease in testosterone hormone level and marked degenerative changes in the seminiferous tubules and the testicular interstitium, with increase in collagen deposits in sovaldi treated rats, and in a more extensive manner in sovaldi-ribavirin treated rats. There was a significant increase of deoxyribonucleic acid (DNA) fragmentation in the treated groups after 10 days. However, there was a non-significant difference in DNA fragmentation in the treated groups after 5 days when compared with control. Immuno-histochemistry detection of caspase-3 showed significant increase in its expression in the treated groups after either 5 or 10 days. This denoted the specificity of caspase-3 immunohistochemistry technique in the detection of early apoptotic changes. It was concluded that sovaldi and sovaldi ribavirin induced gonado toxic effects through induction of DNA fragmentation via up regulation of caspase-3, and that the resulting damaging effects increased with longer duration of drug in take

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Hepatotoxicity and virological breakthrough of HCV following treatment with sofosbuvir, daclatasvir, and ribavirin in patients previously treated for tuberculosis.

The prevalence of hepatitis C virus/tuberculosis (HCV/TB) coinfection has not been estimated globally but few studies highlight the risk of hepatotoxicity following TB treatment or HCV treatment. Previously reported data highlights the risk of drug-induced hepatotoxicity associated with three of the first-line anti-TB agents: rifampin, isoniazid, and pyrazinamide specifically in patients coinfected with HIV and HCV. Thus far, direct-acting antiviral (DAA) drug-induced hepatotoxicity has not been reported in the literature but herein, we observed an unusual case of HCV virological breakthrough and hepatoxicity during treatment with DAA drugs in a patient who has previously been successfully treated for TB.

Structure-activity relationship analysis of mitochondrial toxicity caused by antiviral ribonucleoside analogs.

Recent cases of severe toxicity during clinical trials have been associated with antiviral ribonucleoside analogs (e.g. INX-08189 and balapiravir). Some have hypothesized that the active metabolites of toxic ribonucleoside analogs, the triphosphate forms, inadvertently target human mitochondrial RNA polymerase (POLRMT), thus inhibiting mitochondrial RNA transcription and protein synthesis. Others have proposed that the prodrug moiety released from the ribonucleoside analogs might instead cause toxicity. Here, we report the mitochondrial effects of several clinically relevant and structurally diverse ribonucleoside analogs including NITD-008, T-705 (favipiravir), R1479 (parent nucleoside of balapiravir), PSI-7851 (sofosbuvir), and INX-08189 (BMS-986094). We found that efficient substrates and chain terminators of POLRMT, such as the nucleoside triphosphate forms of R1479, NITD-008, and INX-08189, are likely to cause mitochondrial toxicity in cells, while weaker chain terminators and inhibitors of POLRMT such as T-705 ribonucleoside triphosphate do not elicit strong in vitro mitochondrial effects. Within a fixed 3'-deoxy or 2'-C-methyl ribose scaffold, changing the base moiety of nucleotides did not strongly affect their inhibition constant (Ki) against POLRMT. By swapping the nucleoside and prodrug moieties of PSI-7851 and INX-08189, we demonstrated that the cell-based toxicity of INX-08189 is mainly caused by the nucleoside component of the molecule. Taken together, these results show that diverse 2' or 4' mono-substituted ribonucleoside scaffolds cause mitochondrial toxicity. Given the unpredictable structure-activity relationship of this ribonucleoside liability, we propose a rapid and systematic in vitro screen combining cell-based and biochemical assays to identify the early potential for mitochondrial toxicity.

Identification of Drug-Drug Interactions In Vitro: A Case Study Evaluating the Effects of Sofosbuvir and Amiodarone on hiPSC-Derived Cardiomyocytes.

Drug-drug interactions pose a difficult drug safety problem, given the increasing number of individuals taking multiple medications and the relative complexity of assessing the potential for interactions. For example, sofosbuvir-based drug treatments have significantly advanced care for hepatitis C virus-infected patients, yet recent reports suggest interactions with amiodarone may cause severe symptomatic bradycardia and thus limit an otherwise extremely effective treatment. Here, we evaluated the ability of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) to recapitulate the interaction between sofosbuvir and amiodarone in vitro, and more generally assessed the feasibility of hiPSC-CMs as a model system for drug-drug interactions. Sofosbuvir alone had negligible effects on cardiomyocyte electrophysiology, whereas the sofosbuvir-amiodarone combination produced dose-dependent effects beyond that of amiodarone alone. By comparison, GS-331007, the primary circulating metabolite of sofosbuvir, had no effect alone or in combination with amiodarone. Further mechanistic studies revealed that the sofosbuvir-amiodarone combination disrupted intracellular calcium (Ca2+) handling and cellular electrophysiology at pharmacologically relevant concentrations, and mechanical activity at supra-pharmacological (30x Cmax) concentrations. These effects were independent of the common mechanisms of direct ion channel block and P-glycoprotein activity. These results support hiPSC-CMs as a comprehensive, yet scalable model system for the identification and evaluation of cardioactive pharmacodynamic drug-drug interactions.

Characterization of forced degradation products and in silico toxicity prediction of Sofosbuvir: A novel HCV NS5B polymerase inhibitor.

Sofosbuvir is a direct acting antiviral medication used to treat Hepatitis C viral infection. The present study focuses on the degradation behavior of the drug under various stress conditions (hydrolysis, oxidative, thermal and photolytic) as per International Conference on Harmonization (ICH Q1A (R2)) guidelines. A high performance liquid chromatographic system (HPLC) was used to develop a selective, precise and accurate method for separating all the degradation products. The separation was achieved on a Sunfire™ C18 (150mm×4.6mm×5µm) stationary phase with a mobile phase of 10mM ammonium acetate (pH 5.0) buffer and acetonitrile in gradient elution mode. A quadrupole-time of flight mass analyzer equipped with an electrospray ionization technique was used to propose the structural information based on the MS/MS and accurate mass measurements. Seven degradation products were identified and characterised by LC-ESI-QTOF-MS/MS. In silico toxicity of the drug and its degradation products was determined using TOPKAT and DEREK toxicity prediction softwares. The proposed method was validated as per the ICH Q2 guidelines.