Detection and quantification of Covid-19 antiviral drugs in biological fluids and tissues

Validation of spectrophotometric and colorimetric methods to quantify clindamycin in skin tissue: application to in vitro release and ex vivo dermatokinetic studies from separable effervescent microarray patch loaded bacterially sensitive microparticle

Diabetes mellitus can cause diabetic foot infection (DFI) complications. DFI is generally caused by infection from bacteria and Methicillin-Resistant Staphylococcus aureus (MRSA) which is resistant to several antibiotics. Application therapy of clindamycin (CLY) administration with the oral route has low bioavailability and non-selective distribution of antibiotics towards bacteria intravenously. In this research, CLY was developed into bacterially sensitive microparticles (MPs) which were further incorporated into a separable effervescent microarray patch (SEMAP) system to increase the selective and responsive to DFI-causing bacteria of CLY. To support this formulation, we explore the potential of silver nanoparticles (AgNPs) towards the UV-Vis spectrophotometry method. The analytical method was validated in phosphate-buffered saline (PBS), tryptic soy broth (TSB), and skin tissue to quantify CLY, CLY loaded in microparticle, and SEMAP system. The developed analytical method was suitable for the acceptance criteria of ICH guidelines. The results showed that the correlation coefficients were linear ≥ 0.999. The values of LLOQ towards PBS, TSB, and skin tissue were 2.02 µg/mL, 4.29 µg/mL, and 2.31 µg/mL, respectively. These approaching methods were also found to be accurate and precise without being affected by dilution integrity. The presence of Staphylococcus aureus bacteria culture can produce lipase enzymes that can lysing the microparticle matrix. Drug release studies showed that bacterial infection in the high drug release microparticle sensitive bacteria and high drug retention in ex vivo dermatokinetic in rat skin tissue media. In addition, in vivo studies were required to quantify the CLY inside in further analytical validation methods.

A comparison of the detection and quantification of praziquantel via electrochemical and gas chromatography methods in freshwater and saltwater samples

Two new techniques for analyzing praziquantel (PZQ), an effective antiparasitic drug used in fresh and saltwater aquariums, were optimized and compared. One method was based on voltammetry and the other method used gas chromatography combined with mass spectrometry (GC-MS), although both procedures utilized the same sample pretreatment strategy which involved the PZQ being quantitatively transferred into acetonitrile using solid phase extraction. GC-MS analysis led to lower limits of detection (0.32 μM, 0.10 ppm) and quantification (0.72 μM, 0.22 ppm) compared to voltammetry, although both methods gave acceptable quantification for levels of PZQ > 25 μM (7.8 ppm). GC-MS is preferred for the most accurate determination, but voltammetry may provide a cost-effective alternative for detecting PZQ where on site testing is required.

Simultaneous quantification method for multiple antiviral drugs in serum using isotope dilution liquid chromatography-tandem mass spectrometry

We describe the simultaneous quantification of six antiviral drugs in serum based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The target drugs-hydroxychloroquine, chloroquine, favipiravir, umifenovir, ritonavir, and lopinavir-were extracted and purified from serum with 75 % v/v methanol as the precipitant reagent. The six analytes were clearly separated within 15 min using gradient elution and mixed-mode stationary phase. The measurement accuracy and precision were assured by adopting isotopes as internal standards. The optimized measurement procedure was strictly validated in linearity, sensitivity, accuracy, and precision. To confirm the robustness of the method in matrix, the method was additionally applied to various types of serum, namely hyperlipidemic and hyperglycemic serum. The method was then applied to assess the stability of the drugs in serum in order to set sample handling and storage guides for laboratory testing. Lastly, the method was implemented in different LC-MS systems to confirm its applicability across similar equipment commonly used in clinical testing laboratories. The overall results show that the optimized protocol is suitable for the accurate, simultaneous quantification of the six antiviral drugs in serum, and it is anticipated to satisfactorily serve as a reference protocol for the analysis of a wide range of other antiviral drugs for drug monitoring with various purposes.

A highly sensitive and green electroanalytical method for the determination of favipiravir in pharmaceutical and biological fluids

BACKGROUND

Favipiravir is currently used for the treatment of coronavirus disease-2019 (COVID-19).

OBJECTIVE

A highly sensitive and eco-friendly electroanalytical method was developed to quantify favipiravir.

METHOD

The voltammetric method optimized a sensor composed of reduced graphene oxide / modified carbon paste electrode in the presence of an anionic surfactant, improving the favipiravir detection limit. The investigation reveals that favipiravir-oxidation is a diffusion-controlled irreversible process. The effects of various pH and scan rates on oxidation anodic peak current were investigated.

RESULTS

The developed method offers a wide linear dynamic range of 1.5-420 ng/mL alongside a higher sensitivity with a limit of detection in the nanogram range (0.44 ng/mL) and a limit of quantification in the low nanogram range (1.34 ng/mL).

CONCLUSION

The proposed method was applied for the determination of favipiravir in the dosage form, human plasma and urine samples. The developed method exhibited good selectivity in the presence of two potential electroactive biological interferants, uric acid which increases during favipiravir therapy and the recommended co-administered vitamin C. The organic solvent-free method greenness was evaluated via the Green Analytical Procedure Index, The present work offers a simple, sensitive and environment-friendly method fulfilling green chemistry concepts.

Recent Developments in Semiconductor-Based Photocatalytic Degradation of Antiviral Drug Pollutants

The prevalence of antiviral drugs (ATVs) has seen a substantial increase in response to the COVID-19 pandemic, leading to heightened concentrations of these pharmaceuticals in wastewater systems. The hydrophilic nature of ATVs has been identified as a significant factor contributing to the low degradation efficiency observed in wastewater treatment plants. This characteristic often necessitates the implementation of additional treatment steps to achieve the complete degradation of ATVs. Semiconductor-based photocatalysis has garnered considerable attention due to its promising potential in achieving efficient degradation rates and subsequent mineralization of pollutants, leveraging the inexhaustible energy of sunlight. However, in recent years, there have been few comprehensive reports that have thoroughly summarized and analyzed the application of photocatalysis for the removal of ATVs. This review commences by summarizing the types and occurrence of ATVs. Furthermore, it places a significant emphasis on delivering a comprehensive summary and analysis of the characteristics pertaining to the photocatalytic elimination of ATVs, utilizing semiconductor photocatalysts such as metal oxides, doped metal oxides, and heterojunctions. Ultimately, the review sheds light on the identified research gaps and key concerns, offering invaluable insights to steer future investigations in this field.

Docking Studies and Molecular Dynamics Simulations of Potential Inhibitors from the Brown Seaweed Sargassum polycystum (Phaeophyceae) against PLpro of SARS-CoV-2

The COVID-19 disease is a major problem affecting human health all over the world. Consequently, researchers have been trying to find solutions to treat this pandemic-scale disease. Even if there are vaccines and approved drugs that could decrease the spread of this pandemic, multidisciplinary approaches are still needed to identify new small molecules as alternatives to combat COVID-19, especially those from nature. In this study, we employed computational approaches by screening 17 natural compounds from the tropical brown seaweed Sargassum polycystum known to have anti-viral properties that benefit human health. This study assessed some seaweed natural products that are bound to the PLpro of SARS-CoV-2. By employing pharmacophore and molecular docking, these natural compounds from S. polycystum showed remarkable scores for protein targets with competitive scores compared to X-ray crystallography ligands and well-known antiviral compounds. This study provides insightful information for advanced study and further in vitro examination and clinical investigation for drug development prospects of abundant yet underexploited tropical seaweeds.

Analytical approaches for determination of COVID-19 candidate drugs in human biological matrices

Since the outbreak of the COVID-19 pandemic, the use of antiviral and other available drugs has been considered to combat or reduce the clinical symptoms of patients. In this regard, it would be necessary to choose sensitive and selective analytical techniques for pharmacokinetic and pharmacodynamic studies, monitoring of drug concentration in biological fluids, and determination of the most appropriate dose to achieve the desired effect on the disease. In the present study, the analytical techniques based on spectroscopy and chromatography with different detectors for diagnosis and determination of candidate drugs in the treatment of COVID-19 in human biological fluids are reviewed during the period 2015-2022. Moreover, various sample preparation and extraction techniques, are being used for this purpose, such as protein precipitation (PP), solid-phase extraction (SPE), liquid-liquid extraction (LLE), and QuEChERS (quick, easy, cheap, effective, rugged, and safe) are investigated.

Effects of voriconazole and fluconazole on the pharmacokinetics of almonertinib in rats by UPLC-MS/MS

Almonertinib was included in the first-line treatment of non-small cell lung cancer with EGFR T790M mutations by the Chinese Society of Clinical Oncology in 2021. Considering that immunocompromised lung cancer patients are prone to opportunistic fungal infections, and most triazole antifungal drugs are moderate or strong inhibitors of CYP3A4, this study was conducted to develop and validate an accurate and rapid ultra-performance liquid chromatography tandem mass spectrometry method for quantifying almonertinib in plasma and for investigating the pharmacokinetic changes of almonertinib caused by voriconazole and fluconazole in rats. After liquid-liquid extraction with tert-butyl methyl ether, an XSelect HSS T3 column (2.1 × 100 mm, 2.5 μm, Waters) was used for the chromatographic separation of almonertinib and sorafenib-D₃ (internal standard). The analytes were detected using an AB Sciex Triple Quad 5,500 mass spectrometer in the positive ionization mode. The method exhibited great linearity (0.5-200 ng/ml, r > 0.997) and stability under the established experimental conditions. All validation experiments were in accordance with the guidelines, and the results were all within the acceptable limits. This method was successfully applied to the researches of pharmacokinetics and drug interactions for almonertinib in rats. Voriconazole and fluconazole significantly altered the pharmacokinetic profiles of almonertinib and increased the systemic exposure of almonertinib in rats to different degrees, but further human trials should be conducted to validate the results.

A sustainable approach for the removal methods and analytical determination methods of antiviral drugs from water/wastewater: A review

In the last years, antiviral drugs especially used for the treatment of COVID-19 have been considered emerging contaminants because of their continuous occurrence and persistence in water/wastewater even at low concentrations. Furthermore, as compared to antiviral drugs, their metabolites and transformation products of these pharmaceuticals are more persistent in the environment. They have been found in environmental matrices all over the world, demonstrating that conventional treatment technologies are unsuccessful for removing them from water/wastewater. Several approaches for degrading/removing antiviral drugs have been studied to avoid this contamination. In this study, the present level of knowledge on the input sources, occurrence, determination methods and, especially, the degradation and removal methods of antiviral drugs are discussed in water/wastewater. Different removal methods, such as conventional treatment methods (i.e. activated sludge), advanced oxidation processes (AOPs), adsorption, membrane processes, and combined processes, were evaluated. In addition, the antiviral drugs and these metabolites, as well as the transformation products created as a result of treatment, were examined. Future perspectives for removing antiviral drugs, their metabolites, and transformation products were also considered.

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

A novel stability-indicating, reversed-phase, high-performance liquid chromatography (RP-HPLC) method was developed and validated for the determination of favipiravir in an oral suspension. The effective separation of favipiravir and its degradation products was achieved on a Zorbax Eclipse Plus C18 column (5 μm particle size, 150 mm length × 4.6 mm diameter). The mobile phase was prepared by mixing 5 mM of phosphate buffer (pH 3.5) and methanol in a 75:25 v/v ratio delivered at a 1.0 mL/min flow rate. The eluents were monitored using a photodiode array detector at a wavelength of 322 nm. The stability-indicating nature of this method was evaluated by performing force degradation studies under various stress conditions, such as acidic, alkali, oxidative, thermal, and photolytic degradation. Significant degradation was observed during the alkali stress degradation condition. The degradation products generated during various stress conditions were well separated from the favipiravir peak. In addition, the major degradation product formed under alkali stress conditions was identified using UPLC-ESI-TQ-MS/MS and NMR. Method validation was performed according to the ICH Q2 (R1) guideline requirements. The developed method is simple, accurate, robust, and reliable for routine quality control analysis of favipiravir oral suspensions.

Size characterization of nanomaterials in environmental and biological matrices through non-electron microscopic techniques

Engineered nanomaterials (ENs) can enter the environment, and accumulate in food chains, thereby causing environmental and health problems. Size characterization of ENs is critical for further evaluating the interactions among ENs in biological and ecological systems. Although electron microscope is a powerful tool in obtaining the size information, it has limitations when studying nanomaterials in complex matrices. In this review, we summarized non-electron microscope-based techniques, including chromatography-based, mass spectrometry-based, synchrotron radiation- and neutron-based techniques for detecting the size of ENs in environmental and biological matrices. The advantages and disadvantages of these techniques were highlighted. The perspectives on size characterization of ENs in complex matrices were also presented.

Fast and efficient extract oseltamivir from aquatic products using magnetic covalent organic frameworks/graphene oxide composite prior to liquid chromatography-tandem mass spectrometry analysis

In this work, a magnetic covalent organic framework/graphene oxide composite (MCOF/GO) was rapidly synthesized and developed as a promising candidate for the magnetic solid-phase extraction (MSPE). Combined with HPLC-MS, an efficient and rapid analytical method was established for the determination of oseltamivir (OS) in aquatic products. The resultant composite not only exhibited superior extraction efficiency, but also possessed fast mass transfer kinetic, reducing the pretreatment time greatly. Under optimal conditions, the linear range of the proposed method for OS determination was found to be 0.1-10 μg/kg along with a satisfactory correlation coefficient (R² = 0.997) and a low limit of detection (LOD, 0.035 μg/kg). Furthermore, the established method was utilized to determine OS in Carp, Yellow croaker, and Shrimp, where the recoveries ranged from 87% to 116%. These results demonstrate the splendid application potential of this method to detect antiviral drugs in actual aquatic products.

Annual review of capillary electrophoresis technology in 2021

该文为2021年毛细管电泳(capillary electrophoresis, CE)技术年度回顾。归纳总结了以“capillary electrophoresis-mass spectrometry”或“capillary isoelectric focusing”或“micellar electrokinetic chromatography”或“capillary electrophoresis”为关键词在ISI Web of Science数据库中进行主题检索(排除“capillary electrochromatography”“microchip”和“capillary monolithic column”)得到的2021年CE技术相关研究论文291篇,以及中文期刊《色谱》和《分析化学》中相关研究论文9篇。重点介绍了影响因子(IF)≥10.0的Coordination Chemistry Reviews, Angewandte Chemie-International Edition, Nature Protocols, TrAC-Trends in Analytical Chemistry, Signal Transduction and Targeted Therapy发表的7篇论文;以及影响因子5~10之间的代表性期刊Analytical Chemistry, Analytica Chimica Acta, Talanta和Food Chemistry的42篇论文;对影响因子小于5但CE技术报道较为集中的Journal of Chromatography A和Electrophoresis,国内重要的中文期刊《色谱》和《分析化学》中的代表性工作进行了概述。该文根据国际通用学术水平评价指标之一的影响因子选择期刊,结合期刊发表CE论文代表性工作进行介绍,便于读者快速了解毛细管电泳技术在过去一年的重要研究进展。

Insights on the Quantitative Concurrent Fluorescence-Based Analysis of Anti-COVID-19 Drugs Remdesivir and Favipiravir

We hereby introduce a sensitive fast straightforward spectrofluorometric method for the estimation of remdesivir and favipiravir. The two drugs are prescribed in some regimens to treat COVID‐19 pandemic disease, which is caused by SARS‐CoV‐2. The method is based on the first derivative synchronous spectrofluorimetry approach for the measurement of remdesivir and favipiravir. This was accomplished at 251 nm and 335 nm respectively using the first derivative order at delta lambda of 140 nm. A linear response with a correlation coefficient 0.9994 was achieved between the concentration and the derivative amplitudes in the ranges of 20.0–100.0 ng ml⁻¹ and 40.0–100.0 ng ml⁻¹ for remdesivir and favipiravir, respectively. The methods were validated for different parameters as stated by the pharmacopeial rules and were applied successfully for estimation of the studied drugs in their synthetic mixtures and in spiked human plasma samples. No significant difference was observed between the proposed and comparison methods as revealed from the analysis of data.

A simple and efficient derivatization strategy combined with switchable solvent liquid-liquid microextraction hydroxychloroquine methyl acetate-d3 -based quadruple isotope dilution gas chromatography mass spectrometry for the determination of hydroxychloroquine sulfate in biological fluids

RATIONALE

A derivatization switchable solvent liquid-liquid microextraction quadruple isotope dilution gas chromatography mass spectrometry (D-SS-LLME-ID⁴ -GC/MS) method is presented for the determination of hydroxychloroquine sulfate in human biofluids.

METHODS

While mixing type/period and concentration of NaOH were optimized via a univariate optimization approach, a multivariate optimization approach was used to determine optimum values for relatively more important parameters such as volumes of derivatization agent (acetic anhydride), NaOH and switchable solvent.

RESULTS

Under the optimum experimental conditions, limit of detection and limit of quantification were calculated as 0.03 and 0.09 mg/kg (mass based), respectively. An isotopically labelled material (hydroxychloroquine methyl acetate-d₃ ) was firstly synthesized to be used in ID⁴ experiments which give highly accurate and precise recovery results. After the application of D-SS-LLME-ID⁴ , superior percent recovery results were recorded as 99.9 ± 1.6-101.3 ± 1.2 for human serum, 99.9 ± 1.7-99.8 ± 1.8 for urine and 99.6 ± 1.5-101.0 ± 1.1 for saliva samples.

CONCLUSIONS

The developed D-SS-LLME-ID⁴ -GC/MS method compensates the complicated matrix effects of human biofluids and provides highly accurate quantification of an analyte with precise results.

Micro/nano biomedical devices for point-of-care diagnosis of infectious respiratory diseases

Corona Virus Disease 2019 (COVID-19) has developed into a global pandemic in the last two years, causing significant impacts on our daily life in many countries. Rapid and accurate detection of COVID-19 is of great importance to both treatments and pandemic management. Till now, a variety of point-of-care testing (POCT) approaches devices, including nucleic acid-based test and immunological detection, have been developed and some of them has been rapidly ruled out for clinical diagnosis of COVID-19 due to the requirement of mass testing. In this review, we provide a summary and commentary on the methods and biomedical devices innovated or renovated for the quick and early diagnosis of COVID-19. In particular, some of micro and nano devices with miniaturized structures, showing outstanding analytical performances such as ultra-sensitivity, rapidness, accuracy and low cost, are discussed in this paper. We also provide our insights on the further implementation of biomedical devices using advanced micro and nano technologies to meet the demand of point-of-care diagnosis and home testing to facilitate pandemic management. In general, our paper provides a comprehensive overview of the latest advances on the POCT device for diagnosis of COVID-19, which may provide insightful knowledge for researcher to further develop novel diagnostic technologies for rapid and on-site detection of pathogens including SARS-CoV-2.

Kinetic degradation study for the first licenced anti-influenza polymerase inhibitor, baloxavir marboxil, using HPLC-MS

The first licensed polymerase inhibitor, baloxavir marboxil was recently approved for the treatment of influenza A and B viruses. Furthermore, there is growing interest in testing the antiviral activity of baloxavir marboxil against Coronavirus. Despite its critical clinical value, there is no information on the degradation products, pathways or kinetics of baloxavir marboxil under various stress conditions. In this study, a new HPLC-MS chromatographic method for accurately quantifying baloxavir marboxil in the presence of its degradation products was developed. A study of degradation kinetics revealed that acidic, thermal neutral, and photolytic degradation reactions have zero-order kinetics, whereas basic and oxidative degradation reactions have first-order kinetics. The structural characterization of baloxavir marboxil degradation products was performed by coupling the optimized HPLC method to the triple-quadrupole tandem mass spectrometer. The proposed approach was validated according to the International Council for Harmonisation Q2 (R1) requirements for accuracy, precision, robustness, specificity, and linearity. The proposed approach was successfully used to analyze baloxavir marboxil as raw material and its pharmaceutical dosage form, Xofluza®. This article is protected by copyright. All rights reserved.

A Review on Measures to Rejuvenate Immune System: Natural Mode of Protection Against Coronavirus Infection

SARS-CoV-2, a novel Corona virus strain, was first detected in Wuhan, China, in December 2019. As of December 16, 2021, almost 4,822,472 people had died and over 236,132,082 were infected with this lethal viral infection. It is believed that the human immune system is thought to play a critical role in the initial phase of infection when the viruses invade the host cells. Although some effective vaccines have already been on the market, researchers and many bio-pharmaceuticals are still working hard to develop a fully functional vaccine or more effective therapeutic agent against the COVID-19. Other efforts, in addition to functional vaccines, can help strengthen the immune system to defeat the corona virus infection. Herein, we have reviewed some of those proven measures, following which a more efficient immune system can be better prepared to fight viral infection. Among these, dietary supplements like- fresh vegetables and fruits offer a plentiful of vitamins and antioxidants, enabling to build of a healthy immune system. While the pharmacologically active components of medicinal plants directly aid in fighting against viral infection, supplementary supplements combined with a healthy diet will assist to regulate the immune system and will prevent viral infection. In addition, some personal habits, like- regular physical exercise, intermittent fasting, and adequate sleep, had also been proven to aid the immune system in becoming an efficient one. Maintaining each of these will strengthen the immune system, allowing innate immunity to become a more defensive and active antagonistic mechanism against corona-virus infection. However, because dietary treatments take longer to produce beneficial effects in adaptive maturation, personalized nutrition cannot be expected to have an immediate impact on the global outbreak.

A validated UHPLC-MS/MS method for simultaneous quantification of some repurposed COVID-19 drugs in rat plasma: Application to a pharmacokinetic study

Since the emergence of Corona virus disease (COVID-19) in 2019, a number of medications have been developed and tried to combat the pandemic. In the present study, we develop a LC-MS/MS approach to detect and quantify certain COVID-19 candidate drugs in rat plasma, including Hydroxychloroquine, Favipiravir, Oseltamivir, and Remdesivir. The analytes were separated using Ultra High-Pressure Liquid Chromatography (UHPLC) over a 13-minute run on a C₁₈ column. The extraction solvent for the (QuEChERS) quick, easy, cheap, effective, rugged and safe method was methanol, while the clean-up phase was primary secondary amine (PSA). Satisfactory recoveries were achieved for all compounds ranging from 82.39 to 105.87 %, with standard deviations smaller than 15.7. In terms of precision, accuracy, linearity, matrix effect, and stability, the method was validated according to US FDA criteria. The Limit of Detection (LOD) was determined to be between 0.11 and 10 ppb. The approach was further developed for a modest pharmacokinetic research in laboratory rats, and thus can be suitable for therapeutic drug monitoring in clinical cases under the same treatment.

Analytical Methods for the Determination of Major Drugs Used for the Treatment of COVID-19. A Review

At the beginning of the COVID-19 outbreak (end 2019 - 2020), therapeutic treatments based on approved drugs have been the fastest approaches to combat the new coronavirus pandemic. Nowadays several vaccines are available. However, the worldwide vaccination program is going to take a long time and its success will depend on the vaccine public's acceptance. Therefore, outside of vaccination, the repurposing of existing antiviral, anti-inflammatory and other types of drugs, have been considered an alternative medical strategy for the COVI-19 infection. Due to the broad clinical potential of the drugs, but also to their possible side effects, analytical methods are needed to monitor the drug concentrations in biological fluids and pharmaceutical products. This review deals with analytical methods developed in the period 2015 - July 2021 to detect potential drugs that, according to a literature survey, have been taken into consideration for the treatment of COVID-19. The drugs considered here have been selected on the basis of the number of articles published in the period January 2020-July 2021, using the combination of the keywords: COVID-19 and drugs or SARS-CoV-2 and drugs. A section is also devoted to monoclonal antibodies. Over the period considered, the analytical methods have been employed in a variety of real samples, such as body fluids (plasma, blood and urine), pharmaceutical products, environmental matrices and food.

Menthol-assisted homogenous liquid-liquid microextraction for HPLC/UV determination of favipiravir as an antiviral for COVID-19 in human plasma

Favipiravir is a promising antiviral agent that has been recently approved for treatment of COVID-19 infection. In this study, a menthol-assisted homogenous liquid–liquid microextraction method has been developed for favipiravir determination in human plasma using HPLC/UV. The different factors that could affect the extraction efficiency were studied, including extractant type, extractant volume, menthol amount and vortex time. The optimum extraction efficiency was achieved using 300 µL of tetrahydrofuran, 30 mg of menthol and vortexing for 1 min before centrifuging the sample for 5 min at 3467g. Addition of menthol does not only induce phase separation, but also helps to form reverse micelles to facilitate extraction. The highly polar favipiravir molecules would be incorporated into the hydrophilic core of the formed reverse micelle to be extracted by the non-polar organic extractant. The method was validated according to the FDA bioanalytical method guidelines. The developed method was found linear in the concentration range of 0.1 to 100 µg/mL with a coefficient of determination of 0.9992. The method accuracy and precision were studied by calculating the recovery (%) and the relative standard deviation (%), respectively. The recovery (%) was in the range of 97.1–103.9%, while the RSD (%) values ranged between 2.03 and 8.15 %. The developed method was successfully applied in a bioequivalence study of Flupirava® 200 mg versus Avigan® 200 mg, after a single oral dose of favipiravir administered to healthy adult volunteers. The proposed method was simple, cheap, more eco-friendly and sufficiently sensitive for biomedical application.

A replacement-type electrochemiluminescent aptasensor for lysozyme based on full-electric modification electrode coupled to silica-coated Ru(bpy)32+/silver nanospheres

This research proposed a replacement-type electrochemiluminescent (ECL) aptasensor for lysozyme (LYZ) detection at trace levels based on a full-electric modification electrode (FEMG) coupled to silica-coated Ru(bpy)₃²⁺/silver nanospheres (Ru/SNs@SiO₂). The multi-walled carbon nanotubes-doped-thionine (MWCNTs/PTn) electropolymerized modified electrode was decorated with electrodeposited gold nanoparticles (GNs) to form the FEMG. Then, the FEMG was utilized as sensing substrates for the immobilization of the anti-lysozyme aptamer (LA); the stability and number of LA attaching onto the FEMG were dramatically increased. The ECL measurement was used to evaluate the hybridization reaction of LA and the Ru/SNs@SiO₂ marked DNA probe, and it was noted as I_a. After the combination of the LA with the LYZ, the target-triggered replacement of the DNA probe was actualized and the ECL measurement descended to I_b. The ECL difference (ΔI_ECL = I_a - I_b) before and after the replacement event was utilized for quantitation of LYZ. As a result, the fabricated aptasensor with great sensitivity and specificity achieved a wide linear range (10 fM-10 pM) and a low limit of detection (5 fM). It obtained satisfactory recovery for the detection of LYZ in human serum, and the results were identified with the LYZ ELISA kit. Therefore, the proposed ECL sensor is expected to become a promising approach in the field of biomolecule detection.

Development and Validation of a Rapid HPLC-DAD Method for Determination of Favipiravir in Pharmaceutical Formulation

Objective: The aim of this work was to develop and validate a rapid and simple high-performance liquid chromatography method with a diode- array detector (HPLC-DAD) for determination of favipiravir in bulk and tablet formulations. Methods: The chromatographic analysis was performed at 30 °C with a Poroshell 120EC-C18 column (4.6 x 50 mm, 2.7 µm). The mobile phase was a mixture of 0.1% formic acid in water and 0.1% formic acid in acetonitrile (90:10, v/v). The run time was 5 min at a flow rate of 0.5 mL/min. Results: The proposed method was successfully validated in terms of precision, accuracy, linearity, robustness, limits of detection (LOD) and quantification (LOQ) parameters. The calibration plot was linear over a concentration range of 10-100 µg/mL. The LOD and LOQ values were found to be 0.58 µg/mL and 2.03 µg/mL, respectively. The average recovery values were found to vary from 99.45 percent to 104.29 percent. Conclusion: As a result, it was concluded that the developed method can be used successfully in the determination of favipiravir in pharmaceutical preparations.

Analysis of surfactants by mass spectrometry: Coming to grips with their diversity

Surfactants are surface-active agents widely used in numerous applications in our daily lives as personal care products, domestic, and industrial detergents. To determine complex mixtures of surfactants and their degradation products, unselective and rather insensitive methods, based on colorimetric and complexometric analyses are no longer employable. Analytical methodologies able to determine low concentration levels of surfactants and closely related compounds in complex matrices are required. The recent introduction of robust, sensitive, and selective mass spectrometry (MS) techniques has led to the rapid expansion of the surfactant research field including complex mixtures of isomers, oligomers, and homologues of surfactants as well as their chemically and biodegradation products at trace levels. In this review, emphasis is given to the state-of-the-art MS-based analysis of surfactants and their degradation products with an overview of the current research landscape from traditional methods involving hyphenate techniques (gas chromatography-MS and liquid chromatography-MS) to the most innovative approaches, based on high-resolution MS. Finally, we outline a detailed explanation on the utilization of MS for mechanistic purposes, such as the study of micelle formation in different solvents.

Recent developments in sample preparation techniques combined with high-performance liquid chromatography: A critical review

This review article compares and contrasts sample preparation techniques coupled with high-performance liquid chromatography (HPLC) and describes applications developed in biomedical, forensics, and environmental/industrial hygiene in the last two decades. The proper sample preparation technique can offer valued data for a targeted application when coupled to HPLC and a suitable detector. Improvements in sample preparation techniques in the last two decades have resulted in efficient extraction, cleanup, and preconcentration in a single step, thus providing a pathway to tackle complex matrix applications. Applications such as biological therapeutics, proteomics, lipidomics, metabolomics, environmental/industrial hygiene, forensics, glycan cleanup, etc., have been significantly enhanced due to improved sample preparation techniques. This review looks at the early sample preparation techniques. Further, it describes eight sample preparation technique coupled to HPLC that has gained prominence in the last two decades. They are (1) solid-phase extraction (SPE), (2) liquid-liquid extraction (LLE), (3) gel permeation chromatography (GPC), (4) Quick Easy Cheap Effective Rugged, Safe (QuEChERS), (5) solid-phase microextraction (SPME), (6) ultrasonic-assisted solvent extraction (UASE), and (7) microwave-assisted solvent extraction (MWASE). SPE, LLE, GPC, QuEChERS, and SPME can be used offline and online with HPLC. UASE and MWASE can be used offline with HPLC but have also been combined with the online automated techniques of SPE, LLE, GPC, or QuEChERS for targeted analysis. Three application areas of biomedical, forensics, and environmental/industrial hygiene are reviewed for the eight sample preparation techniques. Three hundred and twenty references on the eight sample preparation techniques published over the last two decades (2001-2021) are provided. Other older references were included to illustrate the historical development of sample preparation techniques.

Development and validation of a sensitive, fast and simple LC-MS / MS method for the quantitation of favipiravir in human serum

Favipiravir is a broad-spectrum inhibitor of viral RNA polymerase. It is currently used as a possible treatment for coronavirus disease 2019 (COVID-19). Pre-clinical or clinical trials of favipiravir require robust, sensitive, and accurate bioanalytical methods for quantitation of favipiravir levels. Recently, several studies have been reported about developing a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring favipiravir levels. However, these methods were validated predominantly for plasma samples, electrospray ionization was operated only in negative or positive mode, and clinical application of these methods has not been applied for patients with COVID-19. This study aimed was to develop a validated LC-MS/MS method for the measurement of favipiravir levels in positive and negative electrospray ionization mode and to perform a pilot study in patients with COVID-19 receiving favipiravir to demonstrate the applicability of this method in biological samples. Simple protein precipitation was used for the extraction of favipiravir from the desired matrix. Favipiravir levels were quantitated using MS / MS with an electrospray ionization source in positive and negative multiple reaction monitoring (MRM) mode. The chromatographic detection was performed on a reverse-phase Phenomenex C18 column (50 mm × 4.6 mm, 5 µm, 100 Å) with gradient elution using 0.1% formic acid in water and 0.1% formic acid in methanol as mobile phase. The method was linear over the concentration ranges of 0.048-50 µg/mL (in negative ionization mode) and 0.062-50 µg/mL (in positive ionization mode) with a correlation coefficient (r2) better than 0.998. The total run time was 3.5 min. The intra-assay and inter-assay %CV values were less than 7.2% and 8.0%, respectively. A simple, rapid and robust LC-MS / MS method was developed for the measurement of favipiravir and validation studies were performed. The validated method was successfully applied for drug level measurement in COVID-19 patients receiving favipiravir.

Analytical Methods for Extraction and Identification of Primary and Secondary Metabolites of Apple (Malus domestica) Fruits: A Review

Apples represent a greater proportion of the worldwide fruit supply, due to their availability on the market and to the high number of existing cultivar varieties and apple-based products (fresh fruit, fruit juice, cider and crushed apples). Several studies on apple fruit metabolites are available, with most of them focusing on their healthy properties’ evaluation. In general, the metabolic profile of apple fruits strongly correlates with most of their peculiar characteristics, such as taste, flavor and color. At the same time, many bioactive molecules could be identified as markers of a specific apple variety. Therefore, a complete description of the analytical protocols commonly used for apple metabolites’ characterization and quantification could be useful for researchers involved in the identification of new phytochemical compounds from different apple varieties. This review describes the analytical methods published in the last ten years, in order to analyze the most important primary and secondary metabolites of Malus domestica fruits. In detail, this review gives an account of the spectrophotometric, chromatographic and mass spectrometric methods. A discussion on the quantitative and qualitative analytical shortcomings for the identification of sugars, fatty acids, polyphenols, organic acids, carotenoids and terpenes found in apple fruits is reported.

Characterization of Quercetin Derivatives in Crossing Combination of Habanero White and Capsicum annuum Peppers and of Anti-Inflammatory and Cytotoxic Activity

The overproduction of reactive oxygen species and the exposure of the human body to free radicals contribute to the aetiology of many chronic health problems, such as cardiovascular disease and cancer. Supplementation with natural antioxidants could be helpful, preventing free-radical-induced tissue damage through the inhibition of the radicals’ formation. Quercetin derivatives have recently been shown to inhibit the production of inflammatory mediators and to reduce the proliferation of tumoral cells, thus being valid compounds to be promoted as dietary supplements. In this work, an HPLC-MS/MS investigation on the derivatives of quercetin in a methanolic extract of peppers deriving from an original crossing combination between Habanero white and Capsicum annuum revealed the occurrence of nine glycoconjugates, either monosaccharide, disaccharide or trisaccharide, as well as an acylated disaccharidic derivative (i.e., quercetin rhamnoside-(feruloyl-hexoside)). Due to the great variability in the quercetin derivatives’ profiles, the Habanero white hybrid pepper extract was subjected to in vitro cytotoxicity assays. The pepper extract under study was proved to have anti-inflammatory activity comparable to that shown by a Capsicum annuum pepper extract since it reduced ROS levels compared to activated cells. Due to its beneficial effects, it could be exploited as a natural constituent of nutraceutical formulations.

Development and Validation of a Method for Quantification of Favipiravir as COVID-19 Management in Spiked Human Plasma

In the current work, a simple, economical, accurate, and precise HPLC method with UV detection was developed to quantify Favipiravir (FVIR) in spiked human plasma using acyclovir (ACVR) as an internal standard in the COVID-19 pandemic time. Both FVIR and ACVR were well separated and resolved on the C18 column using the mobile phase blend of methanol:acetonitrile:20 mM phosphate buffer (pH 3.1) in an isocratic mode flow rate of 1 mL/min with a proportion of 30:10:60 %, v/v/v. The detector wavelength was set at 242 nm. Maximum recovery of FVIR and ACVR from plasma was obtained with dichloromethane (DCM) as extracting solvent. The calibration curve was found to be linear in the range of 3.1-60.0 µg/mL with regression coefficient (r2) = 0.9976. However, with acceptable r2, the calibration data's heteroscedasticity was observed, which was further reduced using weighted linear regression with weighting factor 1/x. Finally, the method was validated concerning sensitivity, accuracy (Inter and Intraday's % RE and RSD were 0.28, 0.65 and 1.00, 0.12 respectively), precision, recovery (89.99%, 89.09%, and 90.81% for LQC, MQC, and HQC, respectively), stability (% RSD for 30-day were 3.04 and 1.71 for LQC and HQC, respectively at -20 °C), and carry-over US-FDA guidance for Bioanalytical Method Validation for researchers in the COVID-19 pandemic crisis. Furthermore, there was no significant difference for selectivity when evaluated at LLOQ concentration of 3 µg/mL of FVIR and relative to the blank.

A Review on Analytical Strategies for the Assessment of Recently Approved Direct Acting Antiviral Drugs

Human beings are in dire need of developing an efficient treatment against fierce viruses like hepatitis C virus (HCV) and Coronavirus (COVID-19). These viruses have already caused the death of over two million people all over the world. Therefore, over the last years, many direct-acting antiviral drugs (DAADs) were developed targeting nonstructural proteins of these two viruses. Among these DAADs, several drugs were found more effective and safer than the others as sofosbuvir, ledipasvir, grazoprevir, glecaprevir, voxilaprevir, velpatasvir, elbasvir, pibrentasvir and remdesivir. The last one is indicated for COVID-19, while the rest are indicated for HCV treatment. Due to the valuable impact of these DAADs, larger number of analytical methods were required to meet the needs of the clinical studies. Therefore, this review will highlight the current approaches, published in the period between 2017 to present, dealing with the determination of these drugs in two different matrices: pharmaceuticals and biological fluids with the challenges of analyzing these drugs either alone, with other drugs, in presence of interferences (pharmaceutical excipients or endogenous plasma components) or in presence of matrix impurities, degradation products and metabolites. These approaches include spectroscopic, chromatographic, capillary electrophoretic, voltametric and nuclear magnetic resonance methods that have been reported during this period. Moreover, the analytical instrumentation and methods used in determination of these DAADs will be illustrated in tabulated forms.

First electrochemical evaluation of favipiravir used as an antiviral option in the treatment of COVID-19: A study of its enhanced voltammetric determination in cationic surfactant media using a boron-doped diamond electrode

Favipiravir, a promising antiviral agent, is undergoing clinical trials for the potential treatment of the novel coronavirus disease 2019 (COVID-19). This is the first report for the electrochemical activity of favipiravir and its electroanalytical sensing. For this purpose, the effect of cationic surfactant, CTAB was demonstrated on the enhanced accumulation of favipiravir at the surface of cathodically pretreated boron-doped diamond (CPT-BDD) electrode. At first, the electrochemical properties of favipiravir were investigated in the surfactant-free solutions by the means of cyclic voltammetry. The compound presented a single oxidation step which is irreversible and adsorption controlled. A systematic study of various operational conditions, such as electrode pretreatment, pH of the supporting electrolyte, concentration of CTAB, accumulation variables, and instrumental parameters on the adsorptive stripping response, was examined using square-wave voltammetry. An oxidation signal at around +1.21 V in Britton-Robinson buffer at pH 8.0 containing 6 × 10^-4 M CTAB allowed to the adsorptive stripping voltammetric determination of favipiravir (after 60 s accumulation step at open-circuit condition). The process could be used in the concentration range with two linear segments of 0.01-0.1 μg mL^-1 (6.4 × 10^-8-6.4 × 10^-7 M) and 0.1-20.0 μg mL^-1 (6.4 × 10^-7-1.3 × 10^-4 M). The limit of detection values were found to be 0.0028 μg mL^-1 (1.8 × 10^-8 M), and 0.023 μg mL^-1 (1.5 × 10^-7 M) for the first and second segments of calibration graph, respectively. The feasibility of developed methodology was tested to the analysis of the commercial tablet formulations and model human urine samples.

Toxic Metals and Non-Communicable Diseases in HIV Population: A Systematic Review

Background and Objectives: HIV has been a serious global health concern since its discovery, with about 37.9 million people living with HIV worldwide as of 2018. Sub-Saharan Africa (SSA) accounts for 68% of the infection and contributed 74% of the 1.5 million deaths in 2013 despite having only 12% of the total world population residing in the region. This systematic review has attempted to determine the association between heavy metal toxicity and the occurrence of non-communicable diseases in the HIV/AIDS population. Materials and Methods: Three databases were systematically searched: PubMed, Scopus, and Google Scholar for studies written in English and published between 1 April 2000 and 12 April 2020. Studies were excluded if the main outcomes were not measured or did not meet the inclusion criteria. Results: All the six included studies are cross-sectional in design, and therefore were evaluated using the STROBE checklist. The data extraction was done using an extraction table; the ratio of female to male participants included in the study was 1.09:1. Qualitative analysis was used due to the heterogeneity in the heavy metal biomarkers and the outcome measured by the included studies. Two studies compared the concentration of heavy metals in HIV-positive and HIV-negative participants while one compared the levels between HAART-naïve and HAART-treated participants, and three determined the association between heavy metal toxicity and non-communicable diseases (liver fibrosis, anaemia, and reproductive parameters, respectively) in HIV-positive patients. Conclusions: Blood lead, cadmium, and mercury levels were higher in HIV-seropositive than -seronegative subjects, whereas serum zinc level was lower in HIV-seropositive than -seronegative subjects, but the causal association between heavy metals and non-communicable diseases in HIV subjects is largely unknown. Interdisciplinary research between nutrition, toxicology, and human health is envisaged for primary and secondary prevention and treatment.

Determination of Antiviral Drugs and Their Metabolites Using Micro-Solid Phase Extraction and UHPLC-MS/MS in Reversed-Phase and Hydrophilic Interaction Chromatography Modes

Two new ultra-high performance liquid chromatography (UHPLC) methods for analyzing 21 selected antivirals and their metabolites were optimized, including sample preparation step, LC separation conditions, and tandem mass spectrometry detection. Micro-solid phase extraction in pipette tips was used to extract antivirals from the biological material of Hanks balanced salt medium of pH 7.4 and 6.5. These media were used in experiments to evaluate the membrane transport of antiviral drugs. Challenging diversity of physicochemical properties was overcome using combined sorbent composed of C₁₈ and ion exchange moiety, which finally allowed to cover the whole range of tested antivirals. For separation, reversed-phase (RP) chromatography and hydrophilic interaction liquid chromatography (HILIC), were optimized using extensive screening of stationary and mobile phase combinations. Optimized RP-UHPLC separation was carried out using BEH Shield RP18 stationary phase and gradient elution with 25 mmol/L formic acid in acetonitrile and in water. HILIC separation was accomplished with a Cortecs HILIC column and gradient elution with 25 mmol/L ammonium formate pH 3 and acetonitrile. Tandem mass spectrometry (MS/MS) conditions were optimized in both chromatographic modes, but obtained results revealed only a little difference in parameters of capillary voltage and cone voltage. While RP-UHPLC-MS/MS exhibited superior separation selectivity, HILIC-UHPLC-MS/MS has shown substantially higher sensitivity of two orders of magnitude for many compounds. Method validation results indicated that HILIC mode was more suitable for multianalyte methods. Despite better separation selectivity achieved in RP-UHPLC-MS/MS, the matrix effects were noticed while using both chromatographic modes leading to signal enhancement in RP and signal suppression in HILIC.

Green micellar solvent-free HPLC and spectrofluorimetric determination of favipiravir as one of COVID-19 antiviral regimens

Quality control (QC) of pharmaceutical products requires fast, sensitive as well as economic methodologies in order to provide high through output at low cost which are the main aspects considered by such economic facilities. Meanwhile, the ecological impacts must be considered by researchers to minimize the hazardous effects of research laboratories. Favipiravir (FAV) is an antiviral agent recently approved for treatment of COVID-19 infections during 2020 pandemic crisis, so the size of its production by international pharmaceutical corporations evolved dramatically within the past few months. Two novel simple, sensitive, and green methods were developed and validated for FAV determination based on solvent-free micellar LC and spectrofluorimetry techniques. To improve FAV native fluorescence, several factors were studied including solvent type, buffering, pH and added surfactants. The best sensitivity for FAV fluorescence was obtained in Britton-Robinson buffer (pH 4) at 436 nm after excitation at 323 nm within concentration range of 20–350 ng mL⁻¹. Another HPLC method was validated using C18-RP (5 µm, 250 × 4.6 mm) stationary phase and solvent-free mobile phase consisting of (0.02 M Brij-35, 0.15 M SDS, and 0.02 M disodium hydrogen phosphate, pH 5.0) isocratically eluted at a flow rate of 1 mL min⁻¹ and detection wavelength of 323 nm. LC method was validated across concentration range of 10–100 µg mL⁻¹ and FAV eluted in 3.8 min. The methods were validated according to the FDA guidelines and were applied successfully for determination of FAV in its marketed tablet dosage forms and in spiked human plasma samples. The proposed methods are eco-friendly since they are typically based on biodegradable reagents in aqueous solvent-free phases, which was proven by their assessment on two recent greenness metrics (GAPI and AGREE) to prove their eco-friendly properties.

HPV Vaccination Attitudes and Behaviors among General Practitioners in Italy

This cross-sectional electronic online or telephone survey assessed the attitudes and behaviors regarding human papillomavirus (HPV) vaccination and the effect of different factors among a nationally representative random sample of 349 general practitioners (GPs) in Italy. A semi-structured interview was performed between September 2018 and October 2020. Almost all respondents considered the HPV vaccine safe with an overall mean value of 8.8, on a scale ranging from 1 to 10, and 59.9% and 32.6% believed that the vaccination was very effective in preventing the related diseases among 12–26 years’ girls and boys. Multivariate logistic regression analysis showed that GPs who had received information about HPV vaccination from scientific journals were more likely to have positive attitude towards the effectiveness of the vaccine in preventing HPV-related diseases in girls between 12–26 years. A large majority (81.5%) of GPs who provided assistance to girls’ patients aged 11–12 years often or always recommend the HPV vaccine to them, and this behavior was more likely to occur in those who believed that the vaccine was very effective in preventing HPV-related diseases in girls between 12–26 years. GPs were more likely to often or always recommend the HPV vaccine to boys aged 11–12 years if they often or always recommended the vaccine to girls aged 11–12 years, if they believed that the vaccine was very effective in preventing HPV-related diseases in boys between 12–26 years, and if they considered the HPV vaccine very safe. GPs should receive information about the HPV immunization to ensure that they routinely communicate with their patient population in order to achieve better coverage rates.