Tackling COVID-19 Using Remdesivir and Favipiravir as Therapeutic Options

Quantum DFT studies on the drug delivery of favipiravir using pristine and functionalized chitosan nanoparticles

Considering the spread of the COVID-19 pandemic, finding new drugs along with the development of effective drug delivery methods can help in the treatment of this disease. For this reason, in this research work, the possibility of drug-delivery of Favipiravir (FP), one of the drugs approved in the treatment of COVID-19, by pristine chitosan (Chit) nanoparticles (NP), and functionalized chitosan nanoparticles with N-acylate, N-methyl, O-acetyl, and Oxazoline functional groups was studied using quantum mechanical DFT methods at B3LYP-D3(BJ)/6-311 + g(d,p) theoretical level in water medium. The QTAIM, NBO, DOS, frontier orbital, conceptual-DFT indices, and non-covalent interaction analysis were further implemented to investigate the possible interactions between FP and Chit NPs. The results show that the adsorption of FP on Chit NPs is done through the creation of hydrogen bonds, and the highest absorption energy of - 18.15 kcal/mol between pristine chitosan and FP. In the case of all functionalized Chit NPs, a decrease in the absorption energy is observed, which is more noticeable in the case of N-acylated and O-acetyl functionalize Chit NPs, and indicates the weakening of the van der Waals interactions for these cases. Considering the compatibility of Chit NPs with the human body and their non-toxicity, as well as the fact that factors such as pH, solubility, the ionic strength, and so on can be adjusted to control the release rate using the functionalized Chit NPs, it seems that the results of this work can be a comprehensive guide to design the drug delivery methods of FP drug using Chit NPs, to reduce the symptoms of COVID-19 disease.

Inhibition of SARS-CoV-2 3CL protease by the anti-viral chimeric protein RetroMAD1

COVID-19 results from SARS-CoV-2, which mutates frequently, challenging current treatments. Therefore, it is critical to develop new therapeutic drugs against this disease. This study explores the interaction between SARS-CoV-2 3CLpro and RetroMAD1, a well-characterized coronavirus protein and potential drug target, using in-silico methods. The analysis through the HDOCK server showed stable complex formation with a binding energy of -12.3, the lowest among reference drugs. The RetroMAD1-3CLpro complex underwent a 100 ns molecular dynamics simulation (MDS) in an explicit solvation system, generating various trajectories, including RMSD, RMSF, hydrogen bonding, radius of gyration, and ligand binding energy. MDS results confirmed intact interactions within the RetroMAD1-3CLpro complex during simulations. In vitro experiments validated RetroMAD1's ability to inhibit 3CLpro enzyme activity and prevent SARS-CoV-2 infection in human bronchial cells. RetroMAD1 exhibited antiviral efficacy comparable to Remdesivir without cytotoxicity at effective concentrations. These results suggest RetroMAD1 as a potential drug candidate against SARS-CoV-2, warranting further in vivo and clinical studies to assess its efficiency.

Femoral head avascular necrosis in COVID-19 survivors: a systematic review

The current systematic review aimed to document published cases of femoral head avascular necrosis (FHAVN) post-COVID-19, to report the COVID-19 disease characteristics and management patients received, and to evaluate how the FHAVN were diagnosed and treated among various reports. A systematic literature review was performed per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines through a comprehensive English literature search on January 2023 through four databases (Embase, PubMed, Cochrane Library, and Scopus), including studies reporting on FHAVN post-COVID-19. Fourteen articles were included, ten (71.4%) were case reports, and four (28.6%) case series reported on 104 patients having a mean age of 42.2 ± 11.7 (14:74) years, in which 182 hip joints were affected. In 13 reports, corticosteroids were used during the COVID-19 management plan for a mean of 24.8 ± 11 (7:42) days, with a mean prednisolone equivalent dose of 1238.5 ± 492.8 (100:3520) mg. A mean of 142.1 ± 107.6 (7:459) days passed between COVID-19 diagnosis and FHAVN detection, and most of the hips were stage II (70.1%), and concomitant septic arthritis was present in eight (4.4%) hips. Most hips (147, 80.8%) were treated non-surgically, of which 143 (78.6%) hips received medical treatment, while 35 (19.2%) hips were surgically managed, 16 (8.8%) core decompression, 13 (7.1%) primary THA, five (2.7%) staged THA and three (1.6%) had first stage THA (debridement and application of antibiotic-loaded cement spacer). The outcomes were acceptable as regards hip function and pain relief. Femoral head avascular necrosis post-COVID-19 infection is a real concern, primarily attributed to corticosteroid usage, besides other factors. Early suspicion and detection are mandatory, as conservative management lines are effective during early stages with acceptable outcomes. However, surgical intervention was required for progressive collapse or patients presented in the late stage.

Revealing the structural and molecular interaction landscape of the favipiravir-RTP and SARS-CoV-2 RdRp complex through integrative bioinformatics: Insights for developing potent drugs targeting SARS-CoV-2 and other viruses

BACKGROUND

The global research community has made considerable progress in therapeutic and vaccine research during the COVID-19 pandemic. Several therapeutics have been repurposed for the treatment of COVID-19. One such compound is, favipiravir, which was approved for the treatment of influenza viruses, including drug-resistant influenza. Despite the limited information on its molecular activity, clinical trials have attempted to determine the effectiveness of favipiravir in patients with mild to moderate COVID-19. Here, we report the structural and molecular interaction landscape of the macromolecular complex of favipiravir-RTP and SARS-CoV-2 RdRp with the RNA chain.

METHODS

Integrative bioinformatics was used to reveal the structural and molecular interaction landscapes of two macromolecular complexes retrieved from RCSB PDB.

RESULTS

We analyzed the interactive residues, H-bonds, and interaction interfaces to evaluate the structural and molecular interaction landscapes of the two macromolecular complexes. We found seven and six H-bonds in the first and second interaction landscapes, respectively. The maximum bond length is 3.79 Å. In the hydrophobic interactions, five residues (Asp618, Asp760, Thr687, Asp623, and Val557) were associated with the first complex and two residues (Lys73 and Tyr217) were associated with the second complex. The mobilities, collective motion, and B-factor of the two macromolecular complexes were analyzed. Finally, we developed different models, including trees, clusters, and heat maps of antiviral molecules, to evaluate the therapeutic status of favipiravir as an antiviral drug.

CONCLUSIONS

The results revealed the structural and molecular interaction landscape of the binding mode of favipiravir with the nsp7-nsp8-nsp12-RNA SARS-CoV-2 RdRp complex. Our findings can help future researchers in understanding the mechanism underlying viral action and guide the design of nucleotide analogs that mimic favipiravir and exhibit greater potency as antiviral drugs against SARS-CoV-2 and other infectious viruses. Thus, our work can help in preparing for future epidemics and pandemics.

Synergy of Small Antiviral Molecules on a Black-Phosphorus Nanocarrier: Machine Learning and Quantum Chemical Simulation Insights

Favipiravir (FP) and Ebselen (EB) belong to a broad range of antiviral drugs that have shown active potential as medications against many viruses. Employing molecular dynamics simulations and machine learning (ML) combined with van der Waals density functional theory, we have uncovered the binding characteristics of these two antiviral drugs on a phosphorene nanocarrier. Herein, by using four different machine learning models (i.e., Bagged Trees, Gaussian Process Regression (GPR), Support Vector Regression (SVR), and Regression Trees (RT)), the Hamiltonian and the interaction energy of antiviral molecules in a phosphorene monolayer are trained in an appropriate way. However, training efficient and accurate models for approximating the density functional theory (DFT) is the final step in using ML to aid in the design of new drugs. To improve the prediction accuracy, the Bayesian optimization approach has been employed to optimize the GPR, SVR, RT, and BT models. Results revealed that the GPR model obtained superior prediction performance with an R2 of 0.9649, indicating that it can explain 96.49% of the data's variability. Then, by means of DFT calculations, we examine the interaction characteristics and thermodynamic properties in a vacuum and a continuum solvent interface. These results illustrate that the hybrid drug is an enabled, functionalized 2D complex with vigorous thermostability. The change in Gibbs free energy at different surface charges and temperatures implies that the FP and EB molecules are allowed to adsorb from the gas phase onto the 2D monolayer at different pH conditions and high temperatures. The results reveal a valuable antiviral drug therapy loaded by 2D biomaterials that may possibly open a new way of auto-treating different diseases, such as SARS-CoV, in primary terms.

Potential RNA-dependent RNA polymerase (RdRp) inhibitors as prospective drug candidates for SARS-CoV-2

The SARS-CoV-2 pandemic is considered as one of the most disastrous pandemics for human health and the world economy. RNA-dependent RNA polymerase (RdRp) is one of the key enzymes that control viral replication. RdRp is an attractive and promising therapeutic target for the treatment of SARS-CoV-2 disease. It has attracted much interest of medicinal chemists, especially after the approval of Remdesivir. This study highlights the most promising SARS-CoV-2 RdRp repurposed drugs in addition to natural and synthetic agents. Although many in silico predicted agents have been developed, the lack of in vitro and in vivo experimental data has hindered their application in drug discovery programs.

From Immunogen to COVID-19 vaccines: Prospects for the post-pandemic era

The COVID-19 pandemic has affected millions of people and posed an unprecedented burden on healthcare systems and economies worldwide since the outbreak of the COVID-19. A considerable number of nations have investigated COVID-19 and proposed a series of prevention and treatment strategies thus far. The pandemic prevention strategies implemented in China have suggested that the spread of COVID-19 can be effectively reduced by restricting large-scale gathering, developing community-scale nucleic acid testing, and conducting epidemiological investigations, whereas sporadic cases have always been identified in numerous places. Currently, there is still no decisive therapy for COVID-19 or related complications. The development of COVID-19 vaccines has raised the hope for mitigating this pandemic based on the intercross immunity induced by COVID-19. Thus far, several types of COVID-19 vaccines have been developed and released to into financial markets. From the perspective of vaccine use in globe, COVID-19 vaccines are beneficial to mitigate the pandemic, whereas the relative adverse events have been reported progressively. This is a review about the development, challenges and prospects of COVID-19 vaccines, and it can provide more insights into all aspects of the vaccines.

Computational Studies of Auto-Active van der Waals Interaction Molecules on Ultra-Thin Black-Phosphorus Film

Using the van der Waals density functional theory, we studied the binding peculiarities of favipiravir (FP) and ebselen (EB) molecules on a monolayer of black phosphorene (BP). We systematically examined the interaction characteristics and thermodynamic properties in a vacuum and a continuum, solvent interface for active drug therapy. These results illustrate that the hybrid molecules are enabled functionalized two-dimensional (2D) complex systems with a vigorous thermostability. We demonstrate in this study that these molecules remain flat on the monolayer BP system and phosphorus atoms are intact. It is inferred that the hybrid FP+EB molecules show larger adsorption energy due to the van der Waals forces and planar electrostatic interactions. The changes in Gibbs free energy at different surface charge fluctuations and temperatures imply that the FP and EB are allowed to adsorb from the gas phase onto the 2D film at high temperatures. Thereby, the results unveiled beneficial inhibitor molecules on two dimensional BP nanocarriers, potentially introducing a modern strategy to enhance the development of advanced materials, biotechnology, and nanomedicine.

Comparison of Chest CT and RT-PCR Assay for Indication of Disease Course of Coronavirus Disease 2019 (COVID-19) Pneumonia

BACKGROUND

COVID-19 patients' courses vary in length, indicating a variable prognosis. The disease duration revealed by different examination methods may differ.

OBJECTIVE

The study aims to compare the differences in the disease course of patients with COVID-19 by chest computed tomography (CT) and reverse-transcription polymerase chain reaction (RT-PCR) assay and explore the factors that affect the course of the illness.

METHODS

106 patients confirmed with COVID-19 were enrolled and divided into two groups (age <60 years and age ≥60 years). The clinical characteristics of the two groups were analyzed. The intervals from symptoms onset to initial positive time point (ISIP), symptoms onset to the initial negative time point (ISIN), and initial positive to initial negative time point (IIPN) indicated by chest CT and RTPCR assay were analyzed. Multiple regression analysis was performed to assess the correlations between independent factors and the intervals.

RESULTS

Chest CT showed an earlier positive time point, a later negative time point, and a longer disease duration than the RT-PCR assay (P<.001, respectively). Older patients over 60 years old showed a later negative time point and a longer disease duration by chest CT than younger patients (P<.01 vs. P<.05, respectively). The CT score and clinical grades of older patients were greater than those of younger patients (P<.001, respectively). Age and clinical grades were significantly correlated with the disease course shown by chest CT (P<.05, respectively), and CT score was positively correlated with the illness course shown by chest CT and RT-PCR assay (P<.01, respectively).

CONCLUSION

The disease course revealed by chest CT and RT-PCR assay was asynchronous. Chest CT showed a 17-day longer period compared to the RT-PCR assay. Older patients had a longer duration than younger ones. A prolonged course is predicted by increasing age, CT score, and clinical grades.

An update on inhibitors targeting RNA-dependent RNA polymerase for COVID-19 treatment: Promises and challenges

The highly transmissible variants of SARS-CoV-2, the causative pathogen of the COVID-19 pandemic, bring new waves of infection worldwide. Identification of effective therapeutic drugs to combat the COVID-19 pandemic is an urgent global need. RNA-dependent RNA polymerase (RdRp), an essential enzyme for viral RNA replication, is the most promising target for antiviral drug research since it has no counterpart in human cells and shows the highest conservation across coronaviruses. This review summarizes recent progress in studies of RdRp inhibitors, focusing on interactions between these inhibitors and the enzyme complex, based on structural analysis, and their effectiveness. In addition, we propose new possible strategies to address the shortcomings of current inhibitors, which may guide the development of novel efficient inhibitors to combat COVID-19.

Molecular dynamics studies reveal structural and functional features of the SARS-CoV-2 spike protein

The SARS-CoV-2 virus is responsible for the COVID-19 pandemic the world experience since 2019. The protein responsible for the first steps of cell invasion, the spike protein, has probably received the most attention in light of its central role during infection. Computational approaches are among the tools employed by the scientific community in the enormous effort to study this new affliction. One of these methods, namely molecular dynamics (MD), has been used to characterize the function of the spike protein at the atomic level and unveil its structural features from a dynamic perspective. In this review, we focus on these main findings, including spike protein flexibility, rare S protein conformational changes, cryptic epitopes, the role of glycans, drug repurposing, and the effect of spike protein variants.

Early Treatment of Favipiravir in COVID-19 Patients Without Pneumonia: A Multicentre, Open-Labelled, Randomized Control Study

We investigated Favipiravir (FPV) efficacy in mild cases of COVID-19 without pneumonia and its effects towards viral clearance, clinical condition, and risk of COVID-19 pneumonia development. PCR-confirmed SARS-CoV-2-infected patients without pneumonia were enrolled (2:1) within 10 days of symptomatic onset into FPV and control arms. The former received 1800 mg FPV twice-daily (BID) on Day 1 and 800 mg BID 5-14 days thereafter until negative viral detection, while the latter received only supportive care. The primary endpoint was time to clinical improvement, defined by a National Early Warning Score (NEWS) of ≤1. 62 patients (41 female) comprised the FPV arm (median age: 32 years, median BMI: 22 kg/m²) and 31 patients (19 female) comprised the control arm (median age: 28 years, median BMI: 22 kg/m²). The median time to sustained clinical improvement, by NEWS, was 2 and 14 days for FPV and control arms respectively (adjusted hazard ratio (aHR) of 2.77, 95% CI 1.57-4.88, P < 0.001). The FPV arm also had significantly higher likelihoods of clinical improvement within 14 days after enrolment by NEWS (79% vs 32% respectively, P < 0.001), particularly female patients (aOR 6.35, 95% CI 1.49-27.07, P < 0.001). 8 (12.9%) and 7 (22.6%) patients in FPV and control arms developed mild pneumonia at a median (range) of 6.5 (1-13) and 7 (1-13) days after treatment, respectively (P = 0.316). All recovered well without complications. We can conclude that early treatment of FPV in symptomatic COVID-19 patients without pneumonia was associated with faster clinical improvement.Trial registration: Thai Clinical Trials Registry identifier: TCTR20200514001..

Rapid and ecofriendly UPLC quantification of Remdesivir, Favipiravir and Dexamethasone for accurate therapeutic drug monitoring in Covid-19 Patient's plasma

Innovative therapeutic protocols to the rapidly spreading coronavirus disease (COVID19) epidemic is highly required all across the world. As demonstrated by clinical studies, Favipiravir (FVP) and Remdesivir (REM) are new antiviral medicines that are effective against COVID-19. REM is the first FDA approved antiviral medicine against COVID-19. In addition to antivirals, corticosteroids such as dexamethasone (DEX), and anticoagulants such as apixaban (PX) are used in multidrug combinations protocols. This work develops and validates simple and selective screening of the four medicines of COVID -19 therapeutic protocol. FVP, REM, DEX, and PX as internal standard in human plasma using UPLC method by C18 column and methanol, acetonitrile, and water acidified by orthophosphate (pH = 4) in a ratio of (15: 35: 50, by volume) as an eluate flowing at 0.3 mL/min. The eluent was detected at 240 nm. The method was linear over (0.1-10 μg/mL) for each of FVP, REM, and DEX. The validation of the UPLC method was assessed in accordance with FDA guidelines. The method can detect as low as down to 0.1 μg/mL for all. The recoveries of the drugs in spiked human plasma ranged from 97.67 to 102.98 percent. Method accuracy and precision were assessed and the drugs showed good stability. The method was proven to be green to the environment after greenness checking by greenness profile and Eco-Scale tool.

Regioselective Synthesis of 2-Aryl-5-cyano-1-(2-hydroxyaryl)-1H-imidazole-4-carboxamides Self-Assisted by a 2-Hydroxyaryl Group

The reactivity of the diaminomaleonitrile-based imines containing hydroxyphenyl substituents with diverse aromatic aldehydes has been explored for the synthesis of novel highly substituted nitrogen heterocycles, which are considered privileged scaffolds in drug discovery. We report here a simple and efficient method for the regiocontrolled synthesis of a variety of 2-aryl-5-cyano-1-(2-hydroxyaryl)-1H-imidazole-4-carboxamides from 2-hydroxybenzylidene imines and aromatic aldehydes. Computational studies on the reaction path revealed that the regioselectivity of the reaction toward the formation of imidazole derivatives instead of 1,2-dihydropyrazines, most likely via a diaza-Cope rearrangement, is driven by the 2-hydroxyaryl group in the scaffold. The latter group promotes the intramolecular abstraction and protonation process in the cycloadduct intermediate, triggering the evolution of the reaction toward the formation of imidazole derivatives.

Drug-Membrane Interactions: Effects of Virus-Specific RNA-Dependent RNA Polymerase Inhibitors Remdesivir and Favipiravir on the Structure of Lipid Bilayers

The two RNA-dependent RNA polymerase inhibitors remdesivir and favipiravir were originally developed and approved as broad-spectrum antiviral drugs for the treatment of harmful viral infections such as Ebola and influenza. With the outbreak of the global SARS-CoV-2 pandemic, the two drugs were repurposed for the treatment of COVID-19 patients. Clinical studies suggested that the efficacy of the drugs is enhanced in the case of an early or even prophylactic application. Because the contact between drug molecules and the plasma membrane is essential for a successful permeation process of the substances and therefore for their intracellular efficiency, drug-induced effects on the membrane structure are likely and have already been shown for other substances. We investigated the impact of remdesivir and favipiravir on lipid bilayers in model and cell membranes via several biophysical approaches. The measurements revealed that the embedding of remdesivir molecules in the lipid bilayer results in a disturbance of the membrane structure of the tested phospholipid vesicles. Nevertheless, in a cell-based assay, the presence of remdesivir induced only weak hemolysis of the treated erythrocytes. In contrast, no experimental indication for an effect on the structure and integrity of the membrane was detected in the case of favipiravir. Regarding potential prophylactic or accompanying use of the drugs in the therapy of COVID-19, the physiologically relevant impacts associated with the drug-induced structural modifications of the membrane might be important to understand side effects and/or low effectivities.

Repurposing dyphylline as a pan-coronavirus antiviral therapy

Background:

In the last two decades, the world has witnessed the emergence of zoonotic corona viruses (CoVs), which cause mild to severe respiratory diseases in humans. Human coronaviruses (HCoVs), mainly from the alpha-CoV and beta-CoV genera, have evolved to be highly pathogenic, such as SARS-CoV-2 causing the COVID-19 pandemic. These coronaviruses carry functional enzymes necessary for the virus life cycle, which represent attractive antiviral targets.

Methods & Results:

We aimed to therapeutically target the main protease (Mpro) of HCoV-NL63 and HCoV-229E (from alpha-CoV genus) and HCoV-OC43 and SARS-CoV-2 (from beta-CoV genus). Through virtual screening, we identified an FDA-approved drug dyphylline, a xanthine derivate, that binds to the catalytic dyad residues; histidine and cystine of the Mpro structures. Importantly, dyphylline dose-dependently inhibited the viral replication in cell culture models infected with the viruses.

Conclusion:

Our findings support the repurposing of dyphylline as a pan-coronavirus antiviral agent.

Omicron: Understanding the latest variant of SARS-CoV-2 and strategies for tackling the infection

The new variant of concern of SARS‐CoV‐2, namely Omicron, has triggered global fear recently. To date, our knowledge of Omicron, particularly of how S glycoprotein mutations affect the infectivity of the virus and the severity of the infection, is far from complete. This hinders our ability to treat the disease and to predict the future state of SARS‐CoV‐2 threats to well‐being and economic stability. Despite this, efforts have been made to unveil the routes of transmission and the efficiency of existing vaccines in tackling Omicron. This article reviews the latest understanding of Omicron and the current status of the use of vaccines and drugs for infection control. It is hoped that this article can offer insights into the development of more effective measures to tackle the pandemic.

Evaluation of favipiravir in the treatment of COVID-19 based on the real-world

BACKGROUND

The role of favipiravir (FVP) as a COVID-19 treatment is recognized but not fully elucidated. We aimed to evaluate whether FVP has definite clinical efficacy and safety in the treatment of COVID-19.

METHODS

International and Chinese databases were searched for randomized controlled clinical trials evaluating FVP for the treatment of COVID-19. A meta-analysis was performed and published literature was synthesized to evaluate the corresponding therapeutic effects.

RESULTS

We included 13 studies (1430 patients in total). Meta-analysis showed that patients with mild-to-moderate disease treated with FVP had a significantly higher viral clearance rate than those in the control group 10 and 14 days after initiation of treatment [RR: 1.13 (95% CI: 1.00, 1.28), P = 0.04; I² = 39% for day 10 and RR: 1.16 (95% CI: 1.04, 1.30), P = 0.008; I² = 38% for day 14] and a significantly shorter hospital stay [MD: -1.52 (95% CI: -2.82, -0.23), P = 0.02; I² = 0%].

CONCLUSIONS

FVP significantly promotes viral clearance and reduces the hospitalization duration in mild-to-moderate COVID-19 patients, which can reduce the risk of severe disease outcomes in patients. However, more importantly, the results showed no benefit of FVP in severe patients, and caution should be taken regarding the treatment options of FVP in severe patients.

Randomized controlled trial of favipiravir, hydroxychloroquine, and standard care in patients with mild/moderate COVID-19 disease

Favipiravir has antiviral activity against influenza, West Nile virus, and yellow fever virus and against flaviviruses. The objective of this pilot study was to compare three arms: favipiravir; hydroxychloroquine; standard care (no specific SARS-CoV-2 treatment) only, in symptomatic patients infected by SARS-CoV-2 in an open-labelled randomized clinical trial. The trial was registered with Bahrain National Taskforce for Combatting COVID-19 on the 7th of May 2020 (registration code: NCT04387760). 150 symptomatic patients with COVID-19 disease were randomized into one of three arms: favipiravir, hydroxychloroquine, or standard care only. The primary outcome was the clinical scale at the end of study follow up (day 14 or on discharge/death) based on a points scale. The secondary outcomes were viral clearance, biochemical parameter changes and mortality at 30-days. Baseline characteristics did not differ between groups. The proportion of patients who achieved a clinical scale < 2 did not differ between groups. The favipiravir-treated and hydroxychloroquine-treated group showed increased viral clearance (OR, 95%CI 2.38, 0.83–6.78, OR, 95%CI 2.15, 0.78–5.92, respectively) compared to standard care, but this was not significant. The biochemical profile did not differ between groups, except for the platelet count (P < 0.03) and uric acid (P < 0.004) that were higher with favipiravir-treatment. Primary or secondary outcome measures did not differ between favipiravir, hydroxychloroquine, and standard therapy for mild to moderate COVID-19 disease; therefore, whilst favipiravir therapy appeared safe with a trend to increased viral clearance, there was no superior therapeutic utility.

Clinical trials registration. NCT04387760. Registration date: 07/05/2020.

Therapeutic dilemmas in addressing SARS-CoV-2 infection: Favipiravir versus Remdesivir

Coronavirus disease 2019 (COVID-19) represents an unmet clinical need, due to a high mortality rate, rapid mutation rate in the virus, increased chances of reinfection, lack of effectiveness of repurposed drugs and economic damage. COVID-19 pandemic has created an urgent need for effective molecules. Clinically proven efficacy and safety profiles have made favipiravir (FVP) and remdesivir (RDV) promising therapeutic options for use against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Even though both are prodrug molecules with an antiviral role based on a similar mechanism of action, differences in pharmacological, pharmacokinetic and pharmacotoxicological mechanisms have been identified. The present study aims to provide a comprehensive comparative assessment of FVP and RDV against SARS-CoV-2 infections, by centralizing medical data provided by significant literature and authorized clinical trials, focusing on the importance of a better understanding of the interactions between drug molecules and infectious agents in order to improve the global management of COVID-19 patients and to reduce the risk of antiviral resistance.

Rational Development of a Carrier-Free Dry Powder Inhalation Formulation for Respiratory Viral Infections via Quality by Design: A Drug-Drug Cocrystal of Favipiravir and Theophylline

Formulating pharmaceutical cocrystals as inhalable dosage forms represents a unique niche in effective management of respiratory infections. Favipiravir, a broad-spectrum antiviral drug with potential pharmacological activity against SARS-CoV-2, exhibits a low aqueous solubility. An ultra-high oral dose is essential, causing low patient compliance. This study reports a Quality-by-Design (QbD)-guided development of a carrier-free inhalable dry powder formulation containing a 1:1 favipiravir-theophylline (FAV-THP) cocrystal via spray drying, which may provide an alternative treatment strategy for individuals with concomitant influenza infections and chronic obstructive pulmonary disease/asthma. The cocrystal formation was confirmed by single crystal X-ray diffraction, powder X-ray diffraction, and the construction of a temperature-composition phase diagram. A three-factor, two-level, full factorial design was employed to produce the optimized formulation and study the impact of critical processing parameters on the resulting median mass aerodynamic diameter (MMAD), fine particle fraction (FPF), and crystallinity of the spray-dried FAV-THP cocrystal. In general, a lower solute concentration and feed pump rate resulted in a smaller MMAD with a higher FPF. The optimized formulation (F1) demonstrated an MMAD of 2.93 μm and an FPF of 79.3%, suitable for deep lung delivery with no in vitro cytotoxicity observed in A549 cells.

SARS-CoV-2 main protease and papain-like protease inhibition by abietane-type diterpenes isolated from the branches of Glyptostrobus pensilis using molecular docking studies

Using various chromatographic methods, five abietane-type diterpenes were isolated from the branches of Glyptostrobus pensilis for the first time. The chemical structures of the isolates were identified by modern spectroscopic techniques, including ¹H and ¹³C nuclear magnetic resonance spectroscopy and by comparison with the literature. In addition, the binding potential of the isolated compounds to replicase protein, SARS-CoV-2 main protease and papain-like protease, were examined using molecular docking studies. In silico results suggested that G. pensilis as well as abietane-types diterpenes are potential candidates for the prevention and treatment of SARS-CoV-2.

Novel environment friendly TLC-densitometric method for the determination of anti-coronavirus drugs "Remdesivir and Favipiravir": Green assessment with application to pharmaceutical formulations and human plasma

A great demand for discovering new therapeutic solutions has been considered all over the world for managing the rapidly progressing COVID-19 pandemic. Remdesivir (REM) and Favipiravir (FAV) are introduced as promising newly developed antiviral agents against the corona virus as evidenced by the clinical findings. Hence, the optimization of an analytical method for their simultaneous determination acquires potential importance in quality control labs and further confirmatory investigations. Herein, a green, sensitive, and selective densitometric method has been proposed and validated for determination of REM and FAV in pharmaceutical formulations and spiked human plasma on normal phase TLC plates. A solvent mixture of ethyl acetate–methanol-ammonia (8:2:0.2 by volume) has been chosen as developing mobile phase system. Well resolved spots have been detected at 235 nm with retardation factors (R_f) of 0.18 and 0.98 for REM and FAV, respectively. A validation study has been carried out in the light of ICH guidelines. Remdesivir and FAV have shown excellent sensitivities with quantitation limits down to 0.12 and 0.07 μg/band, respectively. The developed method has been successfully applied to tablet formulations and spiked plasma with excellent recoveries ranged from 97.21 to 101.31%. The greenness of the method has been evaluated using the standards of greenness profile and Eco-Scale. It has passed the four greenness profile quadrants and achieved 80 score in Eco-Scale.

Broad antiviral and anti-inflammatory activity of Qingwenjiere mixture against SARS-CoV-2 and other human coronavirus infections

BACKGROUND

Qingwenjiere Mixture (QJM) is a traditional Chinese medicine (TCM) that has been shown to have remarkable clinical efficacy against COVID-19. However, little is known about the antiviral and anti-inflammatory activities of QJM against a wider range of human coronavirus (HCoV) strains.

PURPOSE

The study aims to investigate the antiviral and anti-inflammatory activities of QJM, as well as the underlying mechanisms against HCoV infections.

METHODS

The chemical compositions from QJM were analyzed by LC-MS. The inhibitory effect of QJM on infections of HCoV-OC43, HCoV-229E, HCoV-NL63, and SARS-CoV-2 was evaluated in HRT-18 cells, Huh7 cells, LLC-MK2 cells, and Vero-E6 cells, respectively, by using cytopathic effect (CPE) inhibition assay or RT-qPCR detection of viral n, s, or RdRp/Hel genes. The expression of pro-inflammatory cytokines induced by HCoV-OC43, HCoV-229E, and SARS-CoV-2, as well as the host ace2 gene was also determined by RT-qPCR assay. Furthermore, the expression of key molecules in the NF-κB/MAPKs signaling pathways was determined by western blot.

RESULTS

In alcohol-extraction groups of QJM and reference decoction pieces, 53 similar ion peaks were identified, the majority of which were phenylpropanoids, iridoids, and flavonoids. In addition, QJM reduced CPE caused by HCoVs and the expression of viral n genes or N protein. Pretreatment with QJM also exerted inhibitory effect on viral n gene expression. QJM also inhibited the expression of RdRp/Hel and s genes of SARS-CoV-2, as well as the host ace2 gene. Besides, QJM markedly reduced virus-induced mRNA expression of a panel of pro-inflammatory cytokines, such as IL-6, CXCL-8/IL-8, CXCL-10/IP-10, CCL-5/RANTES, TNF-α, IFN-α, CCL-2/MCP-1, CXCL-9/MIG, and IL1-α. We further showed that QJM inhibited the phosphorylation of NF-κB p65, and JNK, ERK 1/2, and p38 MAPKs in HCoV-OC43-infected HRT-18 cells.

CONCLUSIONS

QJM has broad antiviral and anti-inflammatory activity against both common and newly emerged HCoVs possibly by inhibiting the activation of key components in NF-κB/MAPKs signaling pathway. QJM also has a prevention effect against HCoV infections and inhibits the host receptor required for virus entry. These results indicate that QJM may have the therapeutic potential in the treatment of diseases caused by a broad range of HCoVs.

Clinical use of antiviral, antibiotic and immunomodulatory drugs in hospitalized COVID-19 patients: a retrospective study in Bandung, Indonesia

Background: Evidence of highly effective repurposed drugs for coronavirus disease 2019 (COVID-19) is insufficient. However, empirical therapy using antiviral, antibiotic and immunomodulatory drugs is massive. Studies evaluating the clinical use of these drugs in Indonesia are sparse. Methods: We performed a retrospective study using medical records of hospitalized COVID-19 patients from July 2020 to March 2021 in Bandung, Indonesia. Data were collected at relevant timelines: age, sex, comorbid condition, peripheral oxygen saturation (SpO2), and hematology at admission; antiviral, antibiotic, and immunomodulator treatment during hospitalization; length of stay hospitalization (LOS) and death at discharge. Clinical use of the drug regimens included dose, frequency, and duration of therapy. The main outcome of hospitalization care was LOS and death. Results: Out of 249 patients, 43.3% had a comorbid condition, 74.7% had non-severe COVID-19 (SpO2 ≥ 90%), and almost all received antiviral or antibiotic agents. Remdesivir was the most frequent drug composing various antiviral regimens. Patients receiving a combination of remdesivir and favipiravir had lower SpO2 compared to those receiving oseltamivir (p=0.01). The short LOS was associated with remdesivir alone (p=0.03), the combination of favipiravir and oseltamivir (p=0.01), and the combination of intravenous levofloxacin and ceftriaxone (p<0.0001). Immunomodulatory drugs (methylprednisolone, dexamethasone, tocilizumab) were used in 47.1% of patients with low SpO2 (p=0.001). Its use was associated with prolonged LOS (p=0.0043). The increased risk of death in patients treated with the combination of remdesivir and favipiravir (OR 4.1;95%CI 1.4-12.2), and immunomodulatory drugs (OR 6.2; 95%CI 1.7-23.3) was confounded by the baseline characteristics of older age, comorbid condition, SpO2 level, and low lymphocyte number. Conclusions: Some treatment regimens were associated with short LOS, but there were drug regimens which might increase the risk of death. Further study should control the clinical conditions of COVID-19 patients at admission to confirm the outcome of death following drug therapy.

Interface-based design of the favipiravir-binding site in SARS-CoV-2 RNA-dependent RNA polymerase reveals mutations conferring resistance to chain termination

Favipiravir is a broad‐spectrum inhibitor of viral RNA‐dependent RNA polymerase (RdRp) currently being used to manage COVID‐19. Accumulation of mutations in severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RdRp may facilitate antigenic drift, generating favipiravir resistance. Focussing on the chain‐termination mechanism utilized by favipiravir, we used high‐throughput interface‐based protein design to generate > 100 000 designs of the favipiravir‐binding site of RdRp and identify mutational hotspots. We identified several single‐point mutants and designs having a sequence identity of 97%–98% with wild‐type RdRp, suggesting that SARS‐CoV‐2 can develop favipiravir resistance with few mutations. Out of 134 mutations documented in the CoV‐GLUE database, 63 specific mutations were already predicted as resistant in our calculations, thus attaining ˜ 47% correlation with the sequencing data. These findings improve our understanding of the potential signatures of adaptation in SARS‐CoV‐2 against favipiravir.

Metal doped fullerene complexes as promising drug delivery materials against COVID-19

An outbreak of respiratory disorder caused by coronavirus has been named as coronavirus infection 2019 (COVID-19). To find a specific treatment against this disease researchers are at the frontline. To cure COVID-19, favipiravir (FPV) has been reported as an effective drug based on its high recovery rate. Among nanomaterials, fullerene C60 has achieved enormous attention as a drug delivery vehicle due to its good bioavailability and low toxicity. Hence, in this work, we have investigated the potential of metal-doped fullerene as a drug carrier, based on DFT calculations by using M06-2X functional and 6-31G(d) basis set in water media. In this research electronic parameters and adsorption energy of FPV on interaction with metal-doped (Cr, Fe, and Ni) fullerene is studied. The charge transfer between drug and doped fullerene has been studied through electrophilicity indexes. The structural and electronic properties are explored in terms of adsorption energy through frontier molecular orbital (FMO) and density of state (DOS). It is observed that doping of fullerene C60 with Cr, Fe, and Ni metals significantly enhances the drug delivery rate and provides numerous advantages including controlled drug release at specific target sites which minimize the generic collection in vivo and reduce the side effects. Thusly, it is suggested that our designed metal-doped complexes might be efficient candidates as drug delivery materials for COVID-19 infection.

Role of Multifunctional Cytoskeletal Filaments in Coronaviridae Infections: Therapeutic Opportunities for COVID-19 in a Nutshell

A novel coronavirus discovered in 2019 is a new strain of the Coronaviridae family (CoVs) that had not been previously identified in humans. It is known as SARS-CoV-2 for Severe Acute Respiratory Syndrome Coronavirus-2, whilst COVID-19 is the name of the disease associated with the virus. SARS-CoV-2 emerged over one year ago and still haunts the human community throughout the world, causing both healthcare and socioeconomic problems. SARS-CoV-2 is spreading with many uncertainties about treatment and prevention: the data available are limited and there are few randomized controlled trial data on the efficacy of antiviral or immunomodulatory agents. SARS-CoV-2 and its mutants are considered as unique within the Coronaviridae family insofar as they spread rapidly and can have severe effects on health. Although the scientific world has been succeeding in developing vaccines and medicines to combat COVID-19, the appearance and the spread of new, more aggressive mutants are posing extra problems for treatment. Nevertheless, our understanding of pandemics is increasing significantly due to this outbreak and is leading to the development of many different pharmacological, immunological and other treatments. This Review focuses on a subset of COVID-19 research, primarily the cytoskeleton-related physiological and pathological processes in which coronaviruses such as SARS-CoV-2 are intimately involved. The discovery of the exact mechanisms of the subversion of host cells by SARS-CoV-2 is critical to the validation of specific drug targets and effective treatments.

Global landscape of patents related to human coronaviruses

At present, the COVID-19 pandemic is running rampant, having caused 2.18 million deaths. Characterizing the global patent landscape of coronaviruses is essential not only for informing research and policy, given the current pandemic crisis, but also for anticipating important future developments. While patents are a promising indicator of technological knowledge production widely used in innovation research, they are often an underused resource in biological sciences. In this study, we present a patent landscape for the seven coronaviruses known to infect humans. The information included in this paper provides a strong intellectual groundwork for the ongoing development of therapeutic agents and vaccines along with a deeper discussion of intellectual property rights under epidemic conditions. The results show that there has been a rapid increase in human coronavirus patents, especially COVID-19 patents. China and the United States play an outstanding role in global cooperation and patent application. The leading role of academic institutions and government is increasingly apparent. Notable technological issues related to human coronaviruses include pharmacochemical treatment, diagnosis of viral infection, viral-vector vaccines, and traditional Chinese medicine. Furthermore, a critical challenge lies in balancing commercial competition, enterprise profit, knowledge sharing, and public interest.

Novel Polymorph of Favipiravir-An Antiviral Medication

Various solid forms of pharmaceutically important compounds exhibit different physical properties and bioactivity; thus, knowledge of the structural landscape and prediction of spontaneous polymorph transformations for an active pharmaceutical ingredient is of practical value for the pharmaceutical industry. By recrystallization from ethyl acetate, a novel polymorph of 6-fluoro-3-hydroxypyrazine-2-carboxamide (trademark favipiravir, RNA polymerase inhibitor) was obtained and characterized using differential scanning calorimetry (DSC), infra-red spectroscopy and powder X-ray diffraction (XRD) analysis. The favipiravir molecule in two polymorphs realizes similar H-bonding motifs, but the overall H-bonded networks differ. Based on periodic density functional theory calculations, the novel tetragonal polymorph with two interpenetrated H-bonded networks is slightly less stable than the orthorhombic one with the zst topology of the underlying H-bonded net that is in accord with experimentally observed powder XRD patterns of slow conversion of the tetragonal phase to the orthorhombic one. However, topological analysis of net relations revealed that no transformations can be applied to convert H-bonded networks in the experimental unit cells, and DSC data indicate no solid-state reactions at heating.

Favipiravir Effects on the Control of Clinical Symptoms of Hospitalized COVID-19 Cases: An Experience with Iranian Formulated Dosage Form

Coronavirus disease -19 (COVID-19) pandemic, caused by SARS-CoV-2, has gradually spread worldwide, becoming a major public health event. This situation requires designing a novel antiviral agent against the SARS-CoV-2; however, this is time-consuming and the use of repurposed medicines may be promising. One such medicine is favipiravir, primarily introduced as an anti-influenza agent in east world. The aim of this study was to evaluate the efficacy and safety of favipiravir in comparison with lopinavir-ritonavir in SARS-CoV-2 infection. In this randomized clinical trial, 62 patients were recruited. These patients had bilateral pulmonary infiltration with peripheral oxygen saturation lower than 93%. The median time from symptoms onset to intervention initiation was seven days. Favipiravir was not available in the Iranian pharmaceutical market, and it was decided to formulate it at the research laboratory of School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients received favipiravir tablet at a dose of 1600 mg orally twice a day for day one and then 600 mg orally twice a day for days 2 to 6. In the second group, the patients received lopinavir-ritonavir combination tablet at a dose of 200/50 mg twice a day for seven days. Fever, cough, and dyspnea were improved significantly in favipiravir group in comparison with lopinavir-ritonavir group on days four and five. Mortality rate and ICU stay in both groups were similar, and there was no significant difference in this regard (P = 0.463 and P = 0.286, respectively). Chest X-ray improvement also was not significantly different between the two groups. Adverse drug reactions occurred in both groups, and impaired liver enzymes were the most frequent adverse effect. In conclusion, early administration of oral favipiravir may reduce the duration of clinical signs and symptoms in patients with COVID-19 and hospitalization period. The mortality rate also should be investigated in future clinical trials.