A combined assay for quantifying remdesivir and its metabolite, along with dexamethasone, in serum

Determination of anti-SARS-CoV-2 virustatic pharmaceuticals in the aquatic environment using high-performance liquid chromatography high-resolution mass spectrometry

The Covid-19 pandemic has affected the global population since 2019. The rapid development and approval of vaccines has brought relief. Yet, effective cures are still being researched. Even if the pandemic situation may end, SARS-CoV-2 will remain and, thus, continued application of the drugs will lead to emissions of the active ingredients into the aquatic environment, as with other anthropogenic micropollutants. However, a general method for trace analysis of antiviral drugs is still missing. To this purpose, favipiravir, remdesivir, its active metabolite GS-441524, molnupiravir and its active metabolite EIDD-1931 were selected as representative analytes. A method was developed based on solid phase extraction and high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry. Optimization comprised the choice of chromatographic columns, elution gradient, mass spectrometry and tandem mass spectrometry parameters. Solid phase extraction proved suitable for increase in limits of detection and quantitation. amelioration of the limits of detection and quantitation. Matrix effects were investigated applying the optimized method to a wastewater sample with added virustatics. All five compounds could be separated with reversed phase chromatography, whereas EIDD-1931 profited from hydrophilic interaction liquid chromatography. The optimized method yielded limits of detection and quantification of 2.1·10-1, 6.9·10-1 µg·L-1 for favipiravir, 1.8·10-3, 5.5·10-3 µg·L-1 for remdesivir, 1.9·10-3, 7.6·10-3 µg·L-1 for GS-441524, 2.9·10-3, 8.7·10-3 µg·L-1 for molnupiravir, and 1.3·10-1, 3.8·10-1 µg·L-1 for EIDD 1931. The method was first applied to compound stability testing at pH 2.8 and 9.7. At pH 2.8, remdesivir, GS-441524 and molnupiravir proved stable, whereas about 14% of EIDD-1931 and favipiravir were degraded. All five antiviral compounds were almost completely decomposed at pH 9.7. The application of the method was further demonstrated for potential transformation product detection on favipiravir ozonation monitoring.

Recent analytical methodologies for the determination of anti-covid-19 drug therapies in various matrices: a critical review

Since the discovery of the first case infected with severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) in Wuhan, China in December 2019, it has turned into a global pandemic. According to the World Health Organization (WHO) statistics, about 603.7 million confirmed coronavirus cases and 6.4 million deaths have been reported. Remdesivir (RMD) was the first U.S. Food and Drug Administration (FDA) approved antiviral drug for the treatment of coronavirus in pediatrics and adults with different disease severities, ranging from mild to severe, in both hospitalized and non-hospitalized patients. Various drug regimens are used in Covid-19 treatment, all of which rely on the use of antiviral agents including ritonavir (RTN)/nirmatrelvir (NTV) combination, molnupiravir (MLP) and favipiravir (FVP). Optimizing analytical methods for the selective and sensitive quantification of the above-mentioned drugs in pharmaceutical dosage forms and biological matrices is a must in the current pandemic. Several analytical techniques were reported for estimation of antivirals used in Covid-19 therapy. Chromatographic methods include Thin Layer Chromatography (TLC) densitometry, High Performance Thin Layer Chromatography (HPTLC), Reversed Phase-High Performance Liquid Chromatography (RP-HPLC), High Performance Liquid Chromatography Tandem Mass Spectrometry (HPLC-MS/MS) or Ultraviolet detectors (HPLC-UV), Ultra High-Performance Liquid Chromatography (UHPLC-MS/MS) or (UPLC-UV) and Micellar Liquid Chromatography (MLC). In addition to other spectroscopic methods including Paper Spray Mass Spectrometry (PS-MS), UV-Visible Spectrophotometry, and Spectrofluorimetry. Herein, we will focus on the clarification of trendy, simple, rapid, accurate, precise, sensitive, selective, and eco-friendly analytical methods used for the analysis of anti-Covid-19 drugs in dosage forms as well as biological matrices.

Development and validation of a paper spray mass spectrometry method for the rapid quantitation of remdesivir and its active metabolite, GS-441524, in human plasma

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Rapid PS-MS/MS quantification of remdesivir and its active metabolite, GS-441524, directly from plasma.

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No sample preparation, short turn-around time, use of stable isotope-labeled internal standards.

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Robust stability data are presented.

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Suitable for adjusting remdesivir dosage for optimal efficacy and minimal toxicity.

Introduction

Remdesivir (GS-5734) is a nucleoside analog prodrug with antiviral activity against several single-stranded RNA viruses, including the novel severe respiratory distress syndrome virus 2 (SARS-CoV-2). It is currently the only FDA-approved antiviral agent for the treatment of individuals with COVID-19 caused by SARS-CoV-2. However, remdesivir pharmacokinetics/pharmacodynamics (PK/PD) and toxicity data in humans are extremely limited. It is imperative that precise analytical methods for the quantification of remdesivir and its active metabolite, GS-441524, are developed for use in further studies. We report, herein, the first validated anti-viral paper spray-mass spectrometry (PS-MS/MS) assay for the quantification of remdesivir and GS-441524 in human plasma. We seek to highlight the utility of PS-MS/MS technology and automation advancements for its potential future use in clinical research and the clinical laboratory setting.

Methods

Calibration curves for remdesivir and GS-441524 were created utilizing seven plasma-based calibrants of varying concentrations and two isotopic internal standards of set concentrations. Four plasma-based quality controls were prepared in a similar fashion to the calibrants and utilized for validation. No sample preparation was needed. Briefly, plasma samples were spotted on a paper substrate contained within pre-manufactured plastic cassette plates, and the spots were dried for 1 h. The samples were then analyzed directly for 1.2 min utilizing PS-MS/MS. All experiments were performed on a Thermo Scientific Altis triple quadrupole mass spectrometer utilizing automated technology.

Results

The calibration ranges were 20 – 5000 and 100 – 25000 ng/mL for remdesivir and GS-441524, respectively. The calibration curves for the two antiviral agents showed excellent linearity (average R² = 0.99–1.00). The inter- and intra-day precision (%CV) across validation runs at four QC levels for both analytes was less than 11.2% and accuracy (%bias) was within ± 15%. Plasma calibrant stability was assessed and degradation for the 4 °C and room temperature samples were seen beginning at Day 7. The plasma calibrants were stable at −20 °C. No interference, matrix effects, or carryover was discovered during the validation process.

Conclusions

PS-MS/MS represents a useful methodology for rapidly quantifying remdesivir and GS-441524, which may be useful for clinical PK/PD, therapeutic drug monitoring (TDM), and toxicity assessment, particularly during the current COVID-19 pandemic and future viral outbreaks.

Comparative Greenness Metric Estimates for Content Uniformity Testing of Anti-Cov-2, GS-5734 in Commercial Vials: Validated Micellar Electrokinetic Chromatographic Assay

Background

The antiviral drug GS-5734 remdesivir is a new phosphoramidate prodrug developed initially as a treatment for Ebola virus which then proved to have antiviral properties against other viruses. After clinical trials, it was the first antiviral to be approved by the U.S. Food and Drug Administration in 2020 to treat severe coronavirus (COVID-19) cases. The widespread current pandemic gave an urge to its fast production and marketing. Thus, new analytical methods must be available for its analysis in a fast and easy manner with low cost to be applicable in all laboratories.

Objective

In the current study, a green and economic micellar electrokinetic chromatographic (MEKC) method is proposed for remdesivir analysis.

Methods

A fused-silica capillary (58.5 cm × 50 μm id, 50 cm effective length) with 20 mM borate buffer (pH 9) and 25 mM sodium dodecyl sulfate was used under a positive potential of 30 kV at 25°C with detection at 245 nm.

Results

Remdesivir analysis was achieved in approximately 5 min. The method proved to be linear in range of 1–50 μg/mL with correlation coefficient, r > 0.999.

Conclusion

The MEKC method proposed was applied to the analysis of remdesivir in its commercial vials. The method was validated per International Conference on Harmonization guidelines.

Highlights

Green chemistry has been the focus of the analytical community in the past few years. This method is considered green due to its low energy and solvent consumption without sacrificing the method’s sensitivity or selectivity. The method’s green profile has been assessed by different greenness assessment scales to ensure the method is eco-friendly and can be used in the pharmaceutical industry.

Physiologically-Based Pharmacokinetic Modeling Approaches for Patients with SARS-CoV-2 Infection: A Case Study with Imatinib

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, which causes coronavirus disease 2019 (COVID‐19), manifests as mild respiratory symptoms to severe respiratory failure and is associated with inflammation and other physiological changes. Of note, substantial increases in plasma concentrations of α₁‐acid‐glycoprotein and interleukin‐6 have been observed among patients admitted to the hospital with advanced SARS‐CoV‐2 infection. A physiologically based pharmacokinetic (PBPK) approach is a useful tool to evaluate and predict disease‐related changes on drug pharmacokinetics. A PBPK model of imatinib has previously been developed and verified in healthy people and patients with cancer. In this study, the PBPK model of imatinib was successfully extrapolated to patients with SARS‐CoV‐2 infection by accounting for disease‐related changes in plasma α₁‐acid‐glycoprotein concentrations and the potential drug interaction between imatinib and dexamethasone. The model demonstrated a good predictive performance in describing total and unbound imatinib concentrations in patients with SARS‐CoV‐2 infection. PBPK simulations highlight that an equivalent dose of imatinib may lead to substantially higher total drug concentrations in patients with SARS‐CoV‐2 infection compared to that in patients with cancer, while the unbound concentrations remain comparable between the 2 patient populations. This supports the notion that unbound trough concentration is a better exposure metric for dose adjustment of imatinib in patients with SARS‐CoV‐2 infection, compared to the corresponding total drug concentration. Potential strategies for refinement and generalization of the PBPK modeling approach in the patient population with SARS‐CoV‐2 are also provided in this article, which could be used to guide study design and inform dose adjustment in the future.

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.

Environmental Impact of the Reported Chromatographic Methods for the Determination of the First FDA-Approved Therapy for COVID-19 Patients, Remdesivir: A Comparative Study

Remdesivir (REM) is considered the first therapeutic option approved by US Food and Drug Administration (FDA) for clinical care in case of hospitalized patients suffering in COVID-19 epidemic. In the presented multilateral comparative search, four eco friendlessness approaches —National Environmental Methods Index (NEMI), Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI), and Analytical Greenness metric (AGREE) are tested to assess 16 analytical chromatographic procedures reported for the analysis of the commonly used antiviral drug; Remdesivir (REM). The values of testing more than one approach when estimating the eco-friendly characters for analytical methods are illustrated in this study. On the light of the outcomes, ESA and AGREE approaches are recommended as they are easily applied and digitally presented. Furthermore, GAPI is also a reliable tool in terms of comprehensiveness for the whole analytical procedures, from sampling till the final assessment. NEMI is the easiest and fastest greenness evaluation tool; however, the information it provides is particularly of limited scope and sometimes inaccurate. To ensure greenness of chromatographic analytical methods, there must be clear planning beforehand, to reduce chemical hazards sent to environment. Additionally, it is highly recommended in method validation protocols to consider the greenness of a given analytical procedure before releasing to routine use.

The LC-MS/MS analysis for the active metabolite of REM (Nuc) reported by Avataneo et al. and Du et al. proved to be the best bio-analytical methods regarding the environmental aspects depending on the GAPI and AGREE tools. However, the HPLC method for REM analysis in intravenous solution reported by Jitta et al. proved to be the greenest analytical method for determination of REM in the pharmaceutical dosage forms according to the ESA, GAPI, and AGREE tools.

Model-Informed Repurposing of Medicines for SARS-CoV-2: Extrapolation of Antiviral Activity and Dose Rationale for Paediatric Patients

Repurposing of remdesivir and other drugs with potential antiviral activity has been the basis of numerous clinical trials aimed at SARS-CoV-2 infection in adults. However, expeditiously designed trials without careful consideration of dose rationale have often resulted in treatment failure and toxicity in the target patient population, which includes not only adults but also children. Here we show how paediatric regimens can be identified using pharmacokinetic-pharmacodynamic (PKPD) principles to establish the target exposure and evaluate the implications of dose selection for early and late intervention. Using in vitro data describing the antiviral activity and published pharmacokinetic data for the agents of interest, we apply a model-based approach to assess the exposure range required for adequate viral clearance and eradication. Pharmacokinetic parameter estimates were subsequently used with clinical trial simulations to characterise the probability target attainment (PTA) associated with enhanced antiviral activity in the lungs. Our analysis shows that neither remdesivir, nor anti-malarial drugs can achieve the desirable target exposure range based on a mg/kg dosing regimen, due to a limited safety margin and high concentrations needed to ensure the required PTA. To date, there has been limited focus on suitable interventions for children affected by COVID-19. Most clinical trials have defined doses selection criteria empirically, without thorough evaluation of the PTA. The current results illustrate how model-based approaches can be used for the integration of clinical and nonclinical data, providing a robust framework for assessing the probability of pharmacological success and consequently the dose rationale for antiviral drugs for the treatment of SARS-CoV-2 infection in children.