The extensive use of antiviral substances (SASs) during and after the COVID-19 pandemic has increased their release into wastewater systems, raising concerns regarding their persistence and potential ecotoxicological effects. The primary objective of this study was to isolate bacterial strains from activated sludge (AS) that possess the ability to biodegrade SASs. From the AS sample, three bacterial species, Comamonas testosteroni (I2), Bacillus amyloliquefaciens (I3) and Bacillus mycoides (I4), were successfully isolated and identified. These strains were subsequently applied in biodegradation experiments targeting seven SASs: daclatasvir (DCV), darunavir (DRV), favipiravir (FAV), lopinavir (LOP), remdesivir (REM), ritonavir (RIT), and umifenovir (UMI). During the experiments, residual SAS concentrations, microbial growth parameters, physicochemical indicators and ecotoxicity were monitored. All three strains demonstrated substantial biodegradation potential, achieving reductions exceeding 90% for most tested compounds, with particularly low toxicity observed in experiments conducted with AS and Bacillus amyloliquefaciens. These findings highlight the relevance of AS-derived bacteria as promising candidates for enhancing SAS removal in wastewater treatment processes.

Severe fever with thrombocytopenia syndrome (SFTS) is a disease caused by SFTS virus (SFTSV), an RNA virus, and endemic to Asia. The case fatality rate in Japan is estimated to be approximately 27%. Currently, no efficacious drugs are available. Favipiravir (FPV) has the potential to treat SFTS. However, no quantitative studies comparing FPV with conventional treatments have been conducted in the country. We conducted an open-label, interventional study in which patients with SFTS were administered FPV 1800 mg twice on the first day, followed by 800 mg twice daily for nine days. Additionally, we performed a retrospective observational study on patients with SFTS who received the best supportive care (BSC) without FPV treatment by collecting medical data from individuals at the same institutions. Patients aged 20-85 years were recruited, and blood samples were collected on Days 0 (pre-dose), 1, 3, 6, 9, 14, and 27 in the interventional study. Outcomes and laboratory parameters were compared by 1:1 matching using propensity score (PS). Thirty and 78 patients were enrolled in the FPV and the BSC groups, respectively. Twenty-three pairs were identified by PS matching. The risk ratio of fatality for the FPV group compared to the BSC group reduced to 0.500 after matching. Ferritin levels associated with hemophagocytosis severity were significantly different between the FPV and BSC groups on Days 3 to 9 after matching. No concerning serious adverse events were observed in the FPV group.This interventional study has been registered with the Japan Registry of Clinical Trials as jRCT2080223816.

HighlightsCuO2@MnO2 based on a glassy carbon electrode (GCE) was developed for the electrochemical detection of favipiravir (FAV).The sensor exhibited a linear response range of 1–200 μM with a low detection limit of 0.51 μM.The proposed sensor demonstrated high selectivity with no interference from common biomolecules and ions, along with good repeatability and reproducibilityThe method was successfully applied to pharmaceutical tablet samples with high recoveries (96.06%–99.23%), and validated against a standard method without significant differences

Development and validation of a novel isocratic RP-HPLC method using AQbD approach for the quantification of favipiravir.

BackgroundThe Borna disease virus 1 (BoDV-1) causes a rare, but severe form of encephalitis in Germany, characterized by rapid progression, late diagnosis, and a high case fatality. Therapy is experimental and recommendations are lacking. Favipiravir (FPV) suppresses BoDV-1 replication in vitro and has been used in a handful of BoDV-1 patients within individual treatment attempts, but little is known about the drug´s pharmacokinetics in encephalitis.MethodsTo monitor and therefore optimize experimental FPV treatment, we established a liquid chromatography tandem mass spectroscopy (LC–MS/MS) assay for serum and cerebrospinal fluid (CSF), and analyzed stored specimens of two patients with BoDV-1 encephalitis in the context of therapeutic drug monitoring as a pilot investigation.ResultsWe demonstrate for the first time that orally administered FPV reaches the CSF in BoDV-1 encephalitis. However, the half-maximal inhibitory concentration (IC50) for BoDV-1 was met only in one patient, raising questions on significantly higher dosing and/or alternative formulations for effective treatment.ConclusionIn conclusion, monitoring experimental FPV therapy in BoDV-1 encephalitis is feasible and should be performed continuously. Future prospective in-depth (multicenter) studies should include more patients and focus on dose-finding, dose–response relationships, and define a therapeutic index to improve outcomes of this so far nearly uniformly fatal disease.

Does Favipiravir interact with DNA? Design of electrochemical DNA nanobiosensor to investigate the interaction between DNA and Favipiravir used in the treatment of COVID-19.

Advancing green and white assessment: DFT-assisted spectrofluorimetry for accurate favipiravir quantification in human plasma.

Fa vipiravir (FAV), an antiviral for influenza and COVID-19, can provoke hepatotoxicity and nephrotoxicity. Curcumin (CUR) has antioxidant and anti-inflammatory properties that may protect against FAV-induced toxicity. Despite the widespread clinical use of FAV, to our knowledge, no in vivo animal study has yet examined its organ-specific oxidative injury profile in parallel with the putative dual, organ-directed actions of CUR. This study evaluated whether curcumin can mitigate favipiravir-induced oxidative and apoptotic damage in rat liver and kidney. Male Wistar rats received FAV (100mg/kg i.p.) and CUR (100 or 200mg/kg p.o.) for 14days. Serum biochemistry analysis was performed to assess levels of ALT, AST, IL-6, MDA, TNF-α, and GSH. Additionally, histopathological examination and TUNEL assay were conducted on kidney and liver tissues. ALT, AST, and cytokines did not differ among groups. MDA remained unchanged in the FAV-alone group but rose significantly with CUR co-treatment, signifying CUR-driven amplification of oxidative stress, especially in hepatic tissue. Histopathological analysis revealed liver and kidney damage from FAV, with CUR exacerbating liver damage but offering partial protection to kidney structures. The TUNEL assay showed reduced apoptosis in the kidneys with CUR, especially at higher doses. FAV causes sub-clinical liver and kidney injury that is not accompanied by lipid peroxidation or enzyme leakage at 14days. CUR exerts dual actions-mitigating renal apoptosis yet amplifying hepatic lipid peroxidation-highlighting an organ-specific risk-benefit ratio that should be weighed before empirical antioxidant supplementation during FAV therapy.

A novel magnetic biochar derived from orange leaves (MBC-OL) was developed for efficient removal of the antiviral drug Favipiravir (FVP) from wastewater. The adsorbent was synthesized through Zinc chloride/Iron (III) chloride hexahydrate (ZnCl2/FeCl3.6H2O) co-activation followed by pyrolysis at 600°C, producing a material with specific surface area of 13.31m²/g and total pore volume of 0.103cm³/g. Comprehensive characterization via X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Energy Dispersive X-ray (SEM-EDX) confirmed successful incorporation of magnetite (Fe3O4) nanoparticles and abundant oxygen-containing functional groups. Response Surface Methodology (RSM) optimization identified ideal conditions (pH 8.3, adsorbent dose 0.161g/L, contact time 97.7min) achieving 97.5 ± 0.8% FVP removal at initial concentration of 14.1mg/L. Kinetic studies revealed pseudo-first-order (PFO) adsorption (R²=0.917) with maximum capacity reaching 416.67mg/g based on Langmuir isotherm. The material demonstrated exceptional stability, maintaining 93.5 ± 1.2% removal efficiency after 10 regeneration cycles. Characterization of spent adsorbent confirmed preservation of magnetic properties (52 wt% Fe retention) and structural integrity. These findings establish MBC-OL as a sustainable, high-capacity adsorbent for pharmaceutical wastewater treatment, with significant potential for agricultural waste valorization in circular economy applications.

Objective: Favipiravir (FVP), an RNA-dependent RNA polymerase inhibitor with low solubility and bioavailability, was encapsulated and optimized into Nanostructured Lipid Carriers (NLC) to improve solubility and control its release profile. Methods: The FVP-NLC formulation was screened using a 26-2 fractional factorial design with 6 critical parameters at 2 levels, which were solid lipid combination (Glyceryl Monostearate (GMS) and combination with Cetyl Alcohol (CA) (1:1)), liquid lipid combination (Medium-Chain Triglycerides (MCT) oils and combination with Ethyl Oleate (EO) (1:1)), solid to liquid lipid ratio (70:30 to 90:10), concentrations of total lipid (2-5% w/v), surfactant (Tween® 80, 2-5% w/v), and co-surfactant (Labrasol®, 1-2% w/v). Sixteen formulas were obtained. FVP-NLC was fabricated using high-shear homogenization (12,000 rpm for 10 min), tandem ultrasonication (amplitude 40% for 5 min), followed by characterization of particle size, polydispersity index, zeta potential, and entrapment efficiency. The optimum formula was further evaluated for in vitro release and kinetics study, as well as short-term stability study under refrigerator (5±3 °C), room temperature (25±2 °C, 60±5% RH), and climatic chamber (40±2 °C, 75±5% RH) for 15 d. Results: The major contributions of parameters were total lipid (32%), co-surfactant concentration (30%), and solid lipid combination (15%). The best formulation was F3 with total lipid 2% w/v, co-surfactant 2% w/v, and GMS showing small particle size (124.1±1.8 nm), polydispersity index (0.1387±0.0043), and zeta potential (-39.06±2.00 mV), with high entrapment efficiency (85.97±0.06% w/v). In vitro release from F3 demonstrated controlled release with diffusion mechanisms for up to 24 h at pH 7.4, following Korsmeyer-Peppas kinetics (R² = 0.9171, n = 0.231). In addition, the short-term stability study revealed that F3 has consistent physicochemical properties for 15 d in all conditions. Conclusion: The 26-2 fractional factorial design has been successfully utilized in screening FVP-NLC formulation to incorporate FVP into the NLC matrix system.

Combinations of approved oral nucleoside analogues confer potent suppression of alphaviruses in vitro and in vivo.

Background The efficient analytical method for antiviral drug quantification is crucial in pharmaceutical and biomedical research, particularly for ensuring accurate dosage and monitoring therapeutic efficacy. Accurate quantification of these compounds in artificial saliva is essential for pharmacokinetic studies, as saliva-based drug monitoring offers a noninvasive alternative to traditional blood sampling. Objective A novel high-performance liquid chromatographic (HPLC) method for simultaneous analysis of three selected antivirals: Tenofovir Disoproxil Fumarate (TDF), Favipiravir (FAV), Ritonavir (RIT) and internal standard as another antiviral (emtricitabine) in artificial saliva was optimized and validated, including sample preparation using new extraction procedure. Methods The chromatographic separation was achieved with XTerra, C18 (250 × 4.6 mm, 3.5 µm) analytical column (20 °C) at a wavelength of 215 nm, and the mobile phase was composed of 0.1% phosphoric acid, methanol, and an acetonitrile mixture; 32:60:8 (v/v) at a flow rate of 0.8 mL/min. The method was linear over the range of 0.1–1.0 µg/mL. Results The method has been found according to ICH guidelines specific, accurate (recovery, 93.003%–103.357%), sensitive (LOD and LOQ were values found as 0.03 and 0.1 µg/mL, respectively), and precise (RSD; 0.412%–3.175%). Conclusion A validated HPLC method was developed for the precise determination of different antiviral agents in artificial saliva.

Antiviral drugs, especially those used to treat COVID-19, have recently been classified as emerging pollutants due to their persistent presence in water and wastewater. These compounds have been found in environmental matrices around the world, demonstrating that existing treatment methods are ineffective in fully removing them from water and wastewater. Therefore, this study examines the removal of favipiravir (FAV) in synthetic domestic wastewater using a membrane bioreactor (MBR). The MBR was operated at varying initial FAV concentrations (50, 100, and 150 µg/L) and solid retention times (SRTs) (45, 30, and 15 days). FAV concentration was measured in aqueous phase (influent and effluent) and sludge samples. Based on the obtained results, the biological degradation constant and efficiency of pharmaceutical removal were determined. An environmental risk assessment was also conducted. Results showed that FAV degradation rate was slightly decreased with increasing initial FAV concentration. However, FAV was removed > 99% regardless of initial FAV concentration. As the initial FAV concentration increased from 50 µg/L to 150 µg/L, the FAV concentration in sludge samples decreased, ranging from 90.8 μg/g to 41.3 μg/g. FAV removal efficiency increased from 48.9% to 86.4% with increasing SRT. The study of environmental risk quotients (RQ) indicates high risk of FAV (RQ > 1).

In-vivo implementation of the HPTLC methodology to rat plasma for the concurrent determination of a novel combination therapy for the management of COVID-19 (favipiravir and nitazoxanide).

ABSTRACTThis research investigates the drug delivery efficacy for 6‐fluoro‐3‐hydroxy‐2‐pyrazinecarboxamide (favipiravir) in PEGylated bionanocomposites using a predictive modeling approach. The study focuses on understanding the interaction mechanisms between favipiravir (FAV) and polyethylene glycol (PEG)/graphene oxide (GO) (GO/PEG) nanosheets across various environmental conditions. To evaluate drug delivery efficacy, the following key parameters were calculated: adsorption energies ranging from −202.61 to −3.46 kcal/mol indicating the strength of binding between the drug and nanocarrier; net charge transfer values between −0.222 and 0.373 electrons, reflecting the degree of charge migration; release times spanning a wide range from 3.4 × 10−14 to 2.38 × 10132 ms, which impacts the drug release kinetics; and thermodynamic parameters such as changes in Gibbs free energy (ΔG) between 183.34 and 16.95 kcal/mol, and changes in enthalpy (ΔH) between −203.64 and 0.55 kcal/mol, providing insights into the favorability and spontaneity of the drug‐nanocarrier interactions. The results show that incorporating PEG onto GO nanosheets enhances adsorption energies and binding affinities for FAV. Environmental factors and PEGylation influence the charge transfer and noncovalent interactions. PEGylation leads to faster FAV release kinetics. Favorable thermodynamics are observed, especially in aqueous environments. Electronic properties, quantum descriptors, and theoretical spectra provide further insights into molecular interactions.

The pursuit of sustainability in analytical chemistry is a multifaceted, challenging and complex endeavor. This requires continuous and competitive attempts to achieve the sustainable development goals at every step of the analytical methodology by adhering to the principles of green, blue and white analytical chemistry. This also involves assessment of the degree of sustainability using the latest evaluation metrics until finally reaching the design of a trichromatic procedure. The herein illustrated work represents a comparative study between two newly developed normal-phase and reverse-phase HPTLC methods for the simultaneous quantitative determination of Remdesivir (RMD), Favipiravir (FAV) and Molnupiravir (MOL). For normal-phase HPTLC method, the employed mobile phase consisted of ethyl acetate: ethanol: water (9.4:0.4:0.25, v/v), while, for reverse-phase HPTLC procedure, a greener mobile phase was employed consisting of ethanol: water (6:4, v/v). For both methods, detection wavelength of RMD and MOL was 244 nm while FAV was detected at 325 nm. Both methods were validated following the International Council for Harmonisation (ICH) guidelines with respect to linearity, range, accuracy, precision and robustness. The two established methods were proved to be linear over the range of 50-2000 ng/band for FAV and MOL and over the range of 30–800 ng/band for RMD. The excellent linearities were proved by the high values of correlation coefficients not less than 0.99988. The developed methods were successfully applied for the determination of the three drugs in their bulk form and in their pharmaceutical formulations. Furthermore, a thorough comparative and integrative trichromatic evaluation of sustainability of the designed methods was performed. The Analytical Eco-Scale, the novel Modified Green Analytical Procedure Index (MoGAPI) (2024) and the Analytical GREEnness (AGREE) metrics were applied for greenness assessment and the recent Blue Applicability Grade Index (BAGI) (2023) tool was employed for blueness evaluation. Finally, the RGB12 model was implemented for appraisal of whiteness of the developed methods.

Coronavirus disease 2019 (COVID-19) is a disease caused by a virus named SARS-CoV-2. It is very contagious and has quickly spread around the world. COVID-19 most often causes respiratory symptoms that can feel much like a cold, a flu, or pneumonia. Molnupiravir (MLP) and Favipiravir (FAV) are two recently approved drugs for the ongoing COVID-19 pandemic drug combination help to reduce antiviral load with less side effect. MLP and Favipiravir standards subjected to degradation under different stress condition like acidic, basic, oxidative, thermal, and photostability. The current study endeavors to identify and characterize the degradation products of MLP and Favipiravir using Liquid Chromatography-Mass Spectrometry (LC-MS). Method developed and validated as per International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Guideline (ICH) Q2(R1). The high performance liquid chromatography separation was achieved using Phenomenex Gemini 5μ C18 (250mm × 4.6mm, 5μm) column using mobile phase A and mobile phase B (15: 85% V/V) and the composition of mobile phase A: 10mM ammonium acetate and mobile phase B: Acetonitrile (ACN) and methanol 70:30% V/V. Injection volume of 10μL with 1.0mL/min flow rate. The detection wavelength was 275nm and the study was performed at 40°C column temperature. Excellent linear relationship between peak area of MLP and Favipiravir concentration in the range of 5-500μg/mL for both drugs has been observed R2 = 0.9995 and R2 = 0.9996, respectively. Precision, accuracy, and robustness were found to be < 2% in terms of Relative Standard Deviation (RSD) and all other parameter were found within the specified criteria as per ICH guidelines. Proposed method has been successfully applied for quantification of MLP and Favipiravir in the presence of its impurities.

The presence of pharmaceuticals in wastewater raises concerns about the toxicological risks associated with its discharge and reuse. During the COVID-19 pandemic, widespread use of antivirals (ATVs), along with plastic gloves and masks, further contributed to pharmaceuticals in wastewater. Chlorination, commonly used for wastewater disinfection, may alter the toxicity of antivirals in the presence of microplastics (MPs) and complex organics in secondarily treated wastewater. To investigate this, synthetic secondary effluent containing Favipiravir (FAV) and Oseltamivir (OSE) was exposed to various chlorination conditions, both with and without MPs. The changes in the concentrations of FAV and OSE were measured using LC-MS/MS with isotopically labeled standards. Chlorination was more effective in removing Favipiravir (42 ± 4%) than Oseltamivir (26 ± 3%). The ecotoxicological effects were assessed on two species—Aliivibrio fischeri (a bacterium) and Enchytraeus crypticus (a soil invertebrate)—to evaluate potential impacts on aquatic and soil environments, though discharge of or irrigation with treated wastewater, respectively. Results indicated that chlorination of wastewater itself increased toxicity more significantly than the chlorination of antivirals to either species, suggesting that chlorination may not be as beneficial despite its cost-effectiveness. The effects of MPs in chlorinated wastewater on toxicity highlighted the importance of sample matrices in environmental toxicity studies.

BackgroundAlphaviruses, including chikungunya virus (CHIKV), pose a significant global health threat, yet specific antiviral therapies remain unavailable.MethodsWe evaluated combinations of three oral directly acting antiviral drugs (sofosbuvir (SOF), molnupiravir (MPV), and favipiravir (FAV)), which are approved for other indications, against CHIKV, Semliki Forest virus (SFV), Sindbis virus (SINV), and Venezuelan Equine Encephalitis virus (VEEV) in vitro and in vivo. We assessed antiviral efficacy in human skin fibroblasts and liver cells, as well as in a mouse model of CHIKV-induced arthritis.FindingsIn human skin fibroblasts, synergistic antiviral effects were observed for combinations of MPV + SOF and FAV + SOF against CHIKV, and for FAV + SOF against SFV. In human liver cells, FAV + MPV conferred additive to synergistic activity against VEEV and SINV, while SOF synergized with FAV against SINV. In mice, MPV improved CHIKV-induced foot swelling and reduced systemic infectious virus titres. Combination treatment with MPV and SOF significantly reduced swelling and infectious virus titres compared to monotherapies of each drug. Sequencing of CHIKV RNA from joint tissue revealed that MPV caused dose-dependent increases in mutations in the CHIKV genome. Upon combination therapy of MPV with SOF, the number of mutations was significantly lower compared to monotherapy with several higher doses of MPV.InterpretationCombining these approved oral nucleoside analogues confers potent suppression of multiple alphaviruses in vitro and in vivo with enhanced control of viral genetic evolution in face of antiviral pressure. These drug combinations may ultimately lead to the development of potent combinations of pan-family alphavirus inhibitors.FundingThis work was supported by a PhD fellowship granted to S.V. by the Research Foundation – Flanders (FWO) (11D5923N). L.D.C. was also supported by Research Foundation – Flanders (FWO) PhD fellowship (11L1325N). Dr. Polyak and Schiffer are partially supported by R01AI121129.

Antiviral drugs, in particular those used to treat COVID-19, have been categorized as emerging pollutants in recent years due to their persistent presence in water/wastewater. They have been identified in environmental matrices all over the world, proving that current treatment methods cannot eliminate them from water/wastewater. In this study, the degradation of favipiravir (FAV) and ecotoxicity changes in different water matrices were investigated using the UV, UV/H2O2, and UV/Co-doped ZnS quantum dots (QDs) photocatalytic processes. The effects of initial FAV concentration, water matrices, pH, H2O2 concentration, and catalyst amount on the FAV degradation rate were evaluated. Initial FAV concentrations (50, 100, and 150 μg/L) have a slight effect on the FAV degradation rate. The matrix composition significantly reduced the degradation rates and efficiencies for the UV, UV/H2O2, and UV/Co-doped ZnS QDs processes in the following order: wastewater treatment plant (WWTP) effluent > tap water (TW) > distilled water (DW). The pH (4.0, 5.0, 7.0, and 9.0) had a remarkable effect on the degradation rate in all processes. The degradation rate enhanced from 86.3 to 98.1% with increasing pH from 4.0 to 9.0 due to increasing the ionization degree of FAV in the UV process. The maximum FAV degradation rate was obtained at pH 7.0 with removal efficiencies of 93.9 and 100% in UV/H2O2 and UV/Co-doped ZnS QDs processes, respectively. Transformation products of FAV were determined in UV and UV/Co-doped ZnS QDs processes. The toxicity to algae increased with increasing FAV concentrations from 50 to 150 μg/L in distilled water. Growth inhibition rates for 50, 100, and 150 μg/L FAV concentrations were 15.1, 33.3, and 36.3% at 96 h, respectively, without any treatment. After 60 min of the UV process, growth inhibition decreased below 0.5% regardless of concentration. Overall, the UV/Co-doped ZnS QDs process is effective in degrading FAV in all aqueous matrices; however, an initial treatment step is required to remove natural organic matter from actual matrices.