Structural Elucidation of Alkali Degradation Impurities of Favipiravir from the Oral Suspension: UPLC-TQ-ESI-MS/MS and NMR

A newly developed high-performance thin layer chromatographic method for determination of remdesivir, favipiravir and dexamethasone, in spiked human plasma: comparison with the published methods

Co-administration of COVID-19 RNA polymerase inhibitors, remdesivir and favipiravir, has synergistic benefits. Together they reduce viral load and inflammation more effectively than either drug used alone. Corticosteroids like dexamethasone are used alongside antivirals in multidrug combination regimens. A new HPTLC method was utilized to isolate and quantitatively determine the three medicines of the COVID-19 therapeutic protocol, remdesivir, favipiravir and dexamethasone, using the anticoagulant apixaban as an internal standard in human plasma. The mobile phase system used a solvent mixture of ethyl acetate, hexane, and acetic acid (9:1:0.3, by volume). At 254 nm, well-resolved spots with Rf values of 0.3 for remdesivir, 0.64 for dexamethasone, and 0.77 for favipiravir have been observed. To ensure compliance with FDA regulations, a validation study was conducted. Quantitation limits as low as 0.1 µg/band have been achieved with remdesivir and dexamethasone, and 0.2 µg/band with favipiravir, demonstrating excellent sensitivities. From 97.07% to 102.77%, the drugs were recovered from human plasma that had been artificially spiked. The whiteness of the method has been assessed using RGB 12 algorithm and a percentage of whiteness of 95.6% has been obtained.

Enhanced favipiravir drug degradation using the synergy of PbO2-based anodic oxidation and Fe-MOF-based cathodic electro-Fenton

Favipiravir (FAV) is a widely utilized antiviral drug effective against various viruses, including SARS-CoV-2, influenza, and RNA viruses. This article aims to introduce a novel approach, known as Linear-Paired Electrocatalytic Degradation (LPED), as an efficient technique for the electrocatalytic degradation of emerging pollutants. LPED involves simultaneously utilizing a carbon-Felt/Co-PbO2 anode and a carbon-felt/Co/Fe-MOF-74 cathode, working together to degrade and mineralize FAV. The prepared anode and cathode characteristics were analyzed using XPS, SEM, EDX mapping, XRD, LSV, and CV analyses. A rotatable central composite design-based quadratic model was employed to optimize FAV degradation, yielding statistically desirable results. Under optimized conditions (pH = 5, current density = 4.2 mA/cm2, FAV concentration = 0.4 mM), individual processes of cathodic electro-Fenton and anodic oxidation with a CF/Co-PbO2 anode achieved degradation rates of 58.9% and 89.5% after 120 min, respectively. In contrast, using the LPED strategy resulted in a remarkable degradation efficiency of 98.4%. Furthermore, a cyclic voltammetric study of FAV on a glassy carbon electrode was conducted to gather additional electrochemical insights and rectify previously published data regarding redox behavior, pH-dependent properties, and adsorption activities. The research also offers a new understanding of the LPED mechanism of FAV at the surfaces of both CF/Co-PbO2 and CF/Co/Fe-MOF-74 electrodes, utilizing data from cyclic voltammetry and LC-MS techniques. The conceptual strategy of LPED is generalizable in order to the synergism of anodic oxidation and cathodic electro-Fenton for the degradation of other toxic and resistant pollutants.

Advancements in Antiviral Therapy: Favipiravir Sodium in Nasal Formulation

Favipiravir (FPV) is an Active Pharmaceutical Ingredient (API) known to have lower solubility in aqueous solvents. In the current study, efforts were made to generate a crystalline Favipiravir Sodium Salt (NaFPV) for enhanced solubility in aqueous media. The in-house generated NaFPV was characterized by NMR studies and its sodium content was determined by Flame Emission Spectroscopy (FES) as a confirmation of salt formation. Its solubility was determined where-in the solubility of NaFPV in water was about 100 times greater than FVP. FPV and NaFPV nasal spray formulations were prepared and its activity was determined against human coronavirus (hCoV) 229E strain. In the anti-hCoV assay as compared to FPV, NaFPV showed almost threefold higher anti-viral activity than its unmodified counterpart. Accelerated stability and spray pattern characteristics of both the formulations were studied. Interestingly, NaFPV showed higher physical stability during storage at conditions 40 ± 2 °C/ 75% ± 5% RH. The nasal spray formulations of both FPV and NaFPV showed ideal plume geometry and spray pattern of acceptable specifications. Due to its improvement in terms of solubility, NaFPV will have higher rate and extent of absorption, and faster onset of the therapeutic effect and may appear to be a feasible alternative to regular favipiravir for use in solid dosage forms.

Trace level quantification of N-nitrosorasagiline in rasagiline tablets by LC-TQ-MS/MS

Parkinson's disease is a chronic, progressive neurological disease that currently affects about more than 10 million population worldwide. Rasagiline is a selective, irreversible monoamine oxidase type B inhibitor used as monotherapy in early Parkinson's disease. Rasagiline tablets have been recalled from market due to the presence of unacceptable levels of nitrosamine impurity. European Medical Agency has set up very stringent limit 100ng/day of N-nitrosorasagiline (NSRG) in drug product based on its mutagenicity. The analytical methods need to be sufficiently sensitive in order to adequately detect and quantify trace levels of NSRG. A highly sensitive LC-MS/MS method for determination of NSRG in rasagiline tablet formulation was developed by effectively separating on zorbax eclipse XDB C18 column using 0.1% formic acid in mixture of water and acetonitrile (35:65 v/v) in an isocratic mode at 0.5mL/min flow rate. The measurement of NSRG was performed using triple quadrupole mass detection accompanied by electrospray ionization in the multiple reaction monitoring mode. The validation of the method was comprehensive, demonstrating strong linearity across the concentration spectrum of 2 to 200ng/mL for NSRG. The obtained correlation coefficient exceeded 0.998, signifying a robust relationship. Recoveries spanning from 80.0% to 120.0% for NSRG were deemed satisfactory. The developed method was able to detect and quantitate NSRG at a concentration level of 1 to 2ng/mL respectively (1 to 2ppm with respect to 1mg/mL of rasagiline tablet sample concentration). The developed and validated method can be employed for routine quality control testing of rasagiline tablets.

Favipiravir biotransformation by a side-stream partial nitritation sludge: Transformation mechanisms, pathways and toxicity evaluation

Information on biotransformation of antivirals in the side-stream partial nitritation (PN) process was limited. In this study, a side-stream PN sludge was adopted to investigate favipiravir biotransformation under controlled ammonium and pH levels. Results showed that free nitrous acid (FNA) was an important factor that inhibited ammonia oxidation and the cometabolic biodegradation of favipiravir induced by ammonia oxidizing bacteria (AOB). The removal efficiency of favipiravir reached 12.6% and 35.0% within 6 days at the average FNA concentrations of 0.07 and 0.02 mg-N L-1, respectively. AOB-induced cometabolism was the sole contributing mechanism to favipiravir removal, excluding AOB-induced metabolism and heterotrophic bacteria-induced biodegradation. The growth of Escherichia coli was inhibited by favipiravir, while the AOB-induced cometabolism facilitated the alleviation of the antimicrobial activities with the formed transformation products. The biotransformation pathways were proposed based on the roughly identified structures of transformation products, which mainly involved hydroxylation, nitration, dehydrogenation and covalent bond breaking under enzymatic conditions. The findings would provide insights on enriching AOB abundance and enhancing AOB-induced cometabolism under FNA stress when targeting higher removal of antivirals during the side-stream wastewater treatment processes.

Review on the Scale-Up Methods for the Preparation of Solid Lipid Nanoparticles

Solid lipid nanoparticles (SLNs) are an alternate carrier system to liposomes, polymeric nanoparticles, and inorganic carriers. SLNs have attracted increasing attention in recent years for delivering drugs, nucleic acids, proteins, peptides, nutraceuticals, and cosmetics. These nanocarriers have attracted industrial attention due to their ease of preparation, physicochemical stability, and scalability. These characteristics make SLNs attractive for manufacture on a large scale. Currently, several products with SLNs are in clinical trials, and there is a high possibility that SLN carriers will quickly increase their presence in the market. A large-scale manufacturing unit is required for commercial applications to prepare enough formulations for clinical studies. Furthermore, continuous processing is becoming more popular in the pharmaceutical sector to reduce product batch-to-batch differences. This review paper discusses some conventional methods and the rationale for large-scale production. It further covers recent progress in scale-up methods for the synthesis of SLNs, including high-pressure homogenization (HPH), hot melt extrusion coupled with HPH, microchannels, nanoprecipitation using static mixers, and microemulsion-based methods. These scale-up technologies enable the possibility of commercialization of SLNs. Furthermore, ongoing studies indicate that these technologies will eventually reach the pharmaceutical market.