RP-HPLC Assay Method for Remdesivir & Favipiravir Capsules

Revolutionary RP-HPLC Method Validated for Remdesivir and Favipiravir combination Capsule, Ensuring Quality and Accessibility

Published April 15, 2025

A breakthrough in pharmaceutical analysis offers a cost-effective and reliable method for ensuring the quality of Remdesivir and Favipiravir combination capsules, vital in managing viral infections.

Introduction: Addressing the Urgent Need for reliable Antiviral Testing

In the ongoing battle against viral infections, including the flu and, more recently, COVID-19, the combination of Remdesivir and Favipiravir in capsule form has emerged as a crucial therapeutic strategy. However, ensuring the quality and consistency of these medications is paramount. That’s where a newly validated Reverse Phase-high Performance Liquid Chromatographic (RP-HPLC) method steps in, offering a simple, precise, and cost-effective solution for pharmaceutical manufacturers and regulatory agencies alike.

Test method progress is the backbone of analytical procedure in chemical compounds, ensuring that drug products are safe, effective, and consistent. These methods are used to identify, segregate, quantify, and analyze the chemical constituents, making them indispensable for commercial-scale manufacturing. According to ICH Q2(R1) guidelines, “Test methods used for any purpose must be reliable, accurate, precise, robust, stable, configurable for any GLP or GMP premises and must be validated.” This new RP-HPLC method adheres to these stringent standards, promising reliable results and minimizing disruptions during large-scale production.

While UHPLC methods coupled with mass spectrophotometry exist, their limitations in accessibility and broader limits for selectivity, linearity, accuracy, and carryover make them less practical for many pharmaceutical laboratories. The new RP-HPLC method overcomes these hurdles, providing a robust and accessible alternative.

Currently, for capsule dosage form, this oral combination was found to be most effective on the basis of all pharmacopeial parameters studied. The RP-HPLC method C18 column with a mobile phase was used for assay and dissolution test for this combination which is entirely different from single drug substances studied on UV or HPLC technologies. The aim is to establish a reliable RP-HPLC method for the quantitative determination of Favipiravir and Remdesivir in Capsule dosage forms,following ICH guidelines.

Method Operable Design Region (MODR) in Quality by Design (QbD) is a key concept for development of pharmaceuticals. It ensures consistent product quality and define the range of critical process parameters like; solvent selection ratio, reaction temperature and time, pH control, catalyst and mixing speed. Critical material attributes like peak purity, particle size distribution, polymorphic form and optimization for scale up includes; continuous batch monitoring, recoveries and environmental impact, robustness effect. In this study, model validation follows a systematic approach under Quality by Design (QbD) principles. Data collection was analytically verified through ICH guidelines, internal validation was assessed through correlation coefficient and method scaleup was measured through robustness parameters.

Literature survey reveals that only few analytical methods either available as separate drug quantification and no combined HPLC method has yet being studied, so this will be novel method to elute both drug substances separately. The entire HPLC method is used to separate, identify, and quantify compounds within a mixture.

favipiravir in its phosphoribosylated form (Favipiravir-RTP) is an RNA-dependent RNA polymerase inhibitor, which suppresses the RNA polymerase activity. It was approved in Japan as tablet in 2014 for the treatment of influenza infections, and since then, it has been authorized in several other countries for use against various viral diseases, including COVID-19.

Remdesivir was the first anti-viral prodrug to be used for these kinds of viral infections, ongoing studies continue to assess its broader applications and effectiveness against different viral pathogens. In 2019, during COVID-19 in the United States, FDA approved remdesivir as emergency treatment for used in this manner, Intravenous Remdesivir can rapidly achieve therapeutic concentrations in the bloodstream within 24 hours, ensuring a more immediate and potent antiviral effect.

The RP-HPLC Method: A Closer Look

The validated RP-HPLC method utilizes a Kromasil 100A C18 column (250 mm x 4.6 mm,5 μm particle size),along with a mobile phase consisting of acetonitrile,methanol,water,and phosphoric acid. Key parameters include:

• Flow Rate: 1.0 mL/min
• UV Detection Wavelength: 300 nm
• Column Temperature: Ambient

Linearity was established with calibration curves showing a good linear response from 0.02 to 0.06 mg/ml for favipiravir and 0.022 to 0.066 mg/ml for remdesivir, with a correlation coefficient (r) of 1.0000 for both. Average recoveries were an impressive 99.9% for favipiravir and 99.8% for remdesivir in the assay test. The retention time of favipiravir was RT 11.5 minutes and remdesivir 20.95 minutes, tailing factor was not more than 1.5 and resolution of more than 2.0 respectively.

The method’s sensitivity is highlighted by its low limits of detection (LOD) and quantification (LOQ):

Analyte	LOD (mg/mL)	LOQ (mg/mL)
Favipiravir	0.104	0.316
Remdesivir	0.052	0.158

These values demonstrate the method’s ability to accurately detect and quantify even trace amounts of the drugs, a crucial factor in ensuring product quality and patient safety.

Stability and Stress Testing: Ensuring Product Integrity

The study also assessed the stability of Remdesivir and Favipiravir under various stress conditions, including acid, alkali, oxidation, reduction, hydrolysis, high temperature, and humidity. The results indicated that the product is sensitive to these factors, underscoring the importance of proper storage conditions. The recommendation is clear: “The product must be stored under ambient temperature, low humidity, and protected from light exposure.”

implications for the U.S. Pharmaceutical Industry and Patient Care

The validation of this RP-HPLC method has significant implications for the U.S. pharmaceutical industry and, ultimately, for patient care. by providing a cost-effective and reliable means of quality control, the method can help ensure that remdesivir and Favipiravir combination capsules meet the highest standards of safety and efficacy. This is particularly vital in the U.S., where the FDA closely regulates pharmaceutical manufacturing and distribution.

For American patients, this translates to greater confidence in the medications they are taking. Consistent quality control reduces the risk of substandard or counterfeit drugs, ensuring that patients receive the intended therapeutic benefits. In a landscape increasingly concerned with drug pricing, a cost-effective testing method can indirectly contribute to more affordable medications by streamlining the manufacturing process.

Moreover, the method’s robustness and adherence to ICH guidelines facilitate regulatory compliance for U.S.manufacturers seeking to market and distribute these antiviral medications. This can expedite the approval process and get vital treatments to patients faster.

Consider the hypothetical case of a U.S.-based pharmaceutical company producing remdesivir and favipiravir capsules. By adopting this validated RP-HPLC method, the company can:

• Reduce analytical costs compared to more complex methods like LC-MS.
• Enhance process control and minimize batch failures.
• Ensure compliance with FDA regulations.
• Maintain a consistent supply of high-quality medication for American patients.

Recent Developments and Future Directions

Since the initial validation of this RP-HPLC method, recent developments in analytical chemistry have focused on further streamlining the process and improving its sensitivity. For example, researchers are exploring the use of smaller particle size columns and advanced detectors to enhance resolution and reduce analysis time. Additionally, efforts are underway to develop automated sample preparation techniques to minimize human error and improve throughput.

The move towards even faster and more efficient analysis is driven by the increasing demand for rapid drug development and quality control in the face of emerging viral threats. The COVID-19 pandemic underscored the need for agile and responsive pharmaceutical manufacturing, and innovations in analytical methods like this RP-HPLC technique are playing a crucial role in meeting that need.

Conclusion: A Step Forward in Ensuring Antiviral Medication Quality

The validated RP-HPLC method represents a significant advancement in the quality control of Remdesivir and Favipiravir combination capsules. Its simplicity, precision, and cost-effectiveness make it a valuable tool for pharmaceutical manufacturers, regulatory agencies, and healthcare providers. By ensuring the consistent quality and safety of these antiviral medications, this method contributes to improved patient outcomes and a more robust public health response to viral infections in the U.S. and beyond.

© 2025. All rights reserved.

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HPLC Method for Analyzing Remdesivir and Favipiravir: A Detailed Look

A complete examination of a validated analytical method for quantifying two critical antiviral drugs, remdesivir and favipiravir, essential in pharmaceutical quality control and research.

Published: Current Date

Introduction

Remdesivir and favipiravir, both antiviral medications, gained prominence during recent health crises. Accurate quantification of these drugs is crucial for pharmaceutical quality control,research,and ensuring proper dosage in clinical settings. This article delves into a validated High-Performance Liquid Chromatography (HPLC) method for the simultaneous determination of remdesivir and favipiravir, offering insights into its development, validation, and practical applications within the U.S. context.

HPLC is a powerful analytical technique widely used in the pharmaceutical industry to separate, identify, and quantify different components in a mixture. The method described hear focuses on Reverse phase HPLC (RP-HPLC), a common mode that utilizes a non-polar stationary phase and a polar mobile phase.

Materials and Methods

the following materials and methods outline the procedure for the RP-HPLC analysis of remdesivir and favipiravir.

Chromatographic Conditions

• Column: 250 mm × 4.6 mm, 5 µm, C18. C18 columns are widely used in RP-HPLC due to their excellent separation capabilities for a broad range of compounds.
• λ max: 300 nm. This wavelength was chosen for detection as it provides optimal absorbance for both remdesivir and favipiravir.
• Temperature: Ambient. Maintaining ambient temperature simplifies the process and reduces energy consumption.
• Flow Rate: 1 ml/minute. This flow rate provides a balance between separation efficiency and analysis time.
• Injection Volume: 10 µL. A standard injection volume for HPLC analysis.
• Mobile Phase: A mixture of acetonitrile (50 ml): methanol (350 ml): water (100 ml) and 0.5 ml phosphoric acid. The mobile phase composition is critical for achieving optimal separation and peak shape. Phosphoric acid is added to control pH and improve peak symmetry.

Procedure

The procedure involves extracting the drug from capsules, preparing standard and test solutions, and analyzing them using HPLC.

1. Twenty capsules were weighed, and their contents carefully collected and crushed into a powder using a pestle and mortar. This ensures a representative sample for analysis.
2. A quantity of the crushed powder equivalent to the weight of one capsule (550 mg) was dissolved in 40 ml of the mobile phase in a 100 ml flask, then diluted to the mark with the same diluent. this step ensures the drug is properly dissolved and at a suitable concentration for HPLC analysis.
3. The solution was sonicated for approximately 10 minutes to aid in dissolution. Sonication uses sound waves to break down particles and enhance solubility.
4. The solution was filtered through a 0.45-micron membrane filter to remove particulate matter that could damage the HPLC system or interfere with the analysis.
5. 1 ml of the filtrate was pipetted into a 25 ml volumetric flask and diluted to volume with the diluent. This results in a final concentration of 0.04 mg/ml of remdesivir and 0.08 mg/ml of favipiravir.
6. The average amount of drug content per capsule was calculated using a calibration curve obtained from the area of a reference standard solution. This calibration curve relates the peak area to the concentration of the drug.

Preparation of the Standard Solution

Accurately weigh 25 mg of remdesivir and 50 mg of favipiravir into 25 ml volumetric flasks. Add mobile phase to dissolve, sonicate for 5 minutes, and bring the final volume to 25 ml. Pipette 1 ml from this standard stock solution into a 25 ml volumetric flask and dilute with mobile phase to volume.the resulting solution contains 0.04 mg/ml of remdesivir and 0.08 mg/ml of favipiravir.

Preparation of the Test Sample

Weigh powder equivalent to the weight of one capsule containing 100 mg of remdesivir and 200 mg of favipiravir into a 100 ml volumetric flask and dissolve in mobile phase. Sonicate the solution for 10 minutes.Filter the solution through a 0.45-micron membrane filter. Pipette 1 ml of the filtrate into a 25 ml volumetric flask and dilute with mobile phase to volume, resulting in a final concentration of 0.04 mg/ml of remdesivir and 0.08 mg/ml of favipiravir.Inject separately 10 μl of the standard and sample solutions and record peak responses. Calculate the content of remdesivir and favipiravir in the capsules using the following formula:

Percent of remdesivir and favipiravir release = Au/As × Rs/Ru × Pot. of std

Where:

• Au and As are the peak areas of the sample and standard, respectively.
• Rs and Ru are the dilution factors of the standard and sample, respectively.

RP-HPLC Method Development

The optimization process for the HPLC method development for favipiravir and remdesivir initially involved attempts using various solvent systems and column configurations (C8 and C18). However, these were insufficient to achieve chromatographically sound separation and retention for both drug substances. The best retention and separation profile were achieved with the mobile phase consisting of Acetonitrile: Methanol: Water in a ratio of 50:350:100, along with 0.5 ml of phosphoric acid. This mobile phase effectively facilitated the elution of both analytes on a stainless steel kromasil 100A column 4.6×250mm,5µ- C18,Merck,at a wavelength of 300 nm with a flow rate of 1 ml/minute.The principle of “like dissolves like” was employed to ensure analyte stability in the selected solvent. Among potential options,the mobile phase was selected as the diluent for consistency and compatibility across the test method validation. The shortlisted mobile phase composition and column combination provided the robustness required for validation of test parameters such as linearity, precision, accuracy, and specificity. Test method HPLC parameters include Specificity, Solution Stability, Linearity, Range, Precision, Accuracy, Robustness, Limit of detection, Limit of Quantification, Stress Degradation, and System Suitability. Each parameter should be meticulously documented, including raw data, calculations, and results for internal validation protocols.

Results and Discussion

The validated HPLC method demonstrated satisfactory performance across various parameters, ensuring its reliability for quantifying remdesivir and favipiravir.

Specificity

Specificity ensures that the procedure is unaffected by the presence of impurities or excipients. Specificity was performed by running a standard solution (as identification test), sample solution, blank, and mobile phase, comparing with a placebo run, and ensuring the run time was at least in triplicate of the principle peak. The data is depicted in Table 1.

No peak was detected for the mobile phase, blank, and placebo at RT 11.5 and 20.95 minutes, respectively, indicating no interference observed at the specified retention time.

Solution Stability

The test solution was prepared, and a portion was stored at room temperature (25°C) and another at 2–8°C. Both solutions were analyzed after 24, 48, and 72 hours and compared with a freshly prepared reference standard.The % difference in the area of the test solution at each interval was calculated and recorded. The data is shown in Table 2, while the raw data is presented in S1 and S2 Tables.

Linearity and Range

The concentrations of the standard solution were varied across specific percentages of the target concentration: 50%, 75%, 100%, 125%, and 150% of the target value. This confirmed that the HPLC method could provide accurate responses across a range of concentrations. For each concentration, a solution was injected into the HPLC system, and the response (peak area) at 300 nm was recorded. A graph was created with concentration on the X-axis and peak area on the Y-axis. A straight line indicates a consistent, predictable response, crucial for accurate quantification in HPLC analysis. The correlation coefficient (not less than 0.999), y-intercept, slope of the regression line, and residual sum of squares were calculated and reported. The correlation coefficient was 0.9999, well within the acceptance limit of NLT 0.999, and the % RSD of the triplicate assay at each level was less than 2.0%. All values complied with acceptance limits, and a linear response was observed in the range of 50–150%.Raw data is presented in S3 Table.

Precision

precision refers to the consistency and repeatability of results when the same sample is analyzed multiple times under the same conditions. It was evaluated by comparing results from multiple measurements of the same sample to determine how closely the individual results agreed. A different analyst carried out the analysis on a different day, using a different HPLC system. The % of relative standard deviation, confidence interval at 90%, and the absolute difference between the mean results obtained from the repeatability analysis and the result of intermediate precision were calculated. The % RSD for six replicates should not be more than 2.0%. The data is depicted in Table 3, while raw data has been presented in S4 and S5 Tables.

Accuracy

Accuracy measures the exactness of the analytical method. The method is accurate if it provides the true answer. Three replicates of a standard solution of 100% (favipiravir 0.08 mg/ml and remdesivir 0.04 mg/ml, respectively) were injected, and a test solution (80%, 100%, and 120%) was prepared as a spiked assay in triplicate runs. Tested results were tabulated as mean recovery and shown in Table 5. the raw data can be traced in S8 and S9 Tables.

All individual recoveries for favipiravir and remdesivir were found to be within 97.0% and 103.0%. The mean recovery was 99.76% for favipiravir and 99.92% for remdesivir, which was well within the specified limits of 98.0% to 102.0%. The 90% confidence interval was 0.0034 for favipiravir and 0.0028 for remdesivir, and all parameters complied well within specified limits.

Limit of Detection (LOD) and Limit of Quantitation (LOQ)

The LOD is defined as the lowest amount of analyte in a sample that can be detected but not necessarily quantitated under the stated experimental conditions.The LOQ is defined as the lowest amount of analyte in a sample that can be quantitatively steadfast with suitable precision and accuracy. LOD and LOQ were calculated using the formulas:

LOD = 3.3 × σ/S

LOQ = 10 × σ/S

Where:

• σ = the standard deviation of the response
• S = the slope of the calibration curve

The LOD for remdesivir and favipiravir was found to be 0.01 µg/ml, and the LOQ was found to be 0.03 µg/ml. This shows that the method is sensitive enough to detect and quantify low concentrations of both drugs.

Robustness

Robustness is the measure of the capacity of the method to remain unaffected by small, but purposeful variations in method parameters and provides an indication of its reliability during normal usage. To determine the robustness of the HPLC method, several parameters were varied, including the flow rate, mobile phase composition, and column temperature. The impact of these changes on the resolution, peak symmetry, and retention time of remdesivir and favipiravir was evaluated. The method proved to be robust, as small variations in these parameters did not significantly affect the performance of the method.

Forced Degradation Study

Forced degradation studies are used to evaluate the stability of pharmaceutical compounds under various stress conditions, such as acid, base, heat, and oxidation. These studies help to identify potential degradation products and assess the stability-indicating nature of the analytical method. Forced degradation studies were conducted by exposing remdesivir and favipiravir to various stress conditions, and the resulting degradation products were analyzed using the HPLC method. The method“`html

Validated RP-HPLC Method for Analyzing remdesivir and Favipiravir Co-Loaded Capsules: A Critical Tool for Quality Control and Stability Testing

By Archyde News Journalist

2024

Introduction

In the ongoing effort to combat viral infections, reliable analytical methods are crucial for ensuring the quality and efficacy of pharmaceutical products. A recent study details the development and validation of a Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) method for the simultaneous analysis of remdesivir and favipiravir in co-loaded capsules. This method offers a simple, rapid, and reproducible approach for quality control and stability testing, addressing a critical need in pharmaceutical analysis.

The development of such methods aligns with broader efforts to enhance pharmaceutical quality and safety, echoing sentiments shared by industry experts. As Fitzsimons noted in the International Journal for Quality in Health Care, “Quality and safety in the time of Coronavirus: design better, learn faster.” This highlights the importance of efficient and reliable analytical techniques in ensuring patient safety and drug efficacy.

For U.S. readers,this research has direct implications for the pharmaceutical industry and regulatory bodies like the Food and Drug Governance (FDA). Accurate and reliable methods for drug analysis are essential for ensuring that medications available to American patients meet stringent quality standards.

Method development and Optimization

The RP-HPLC method was developed using a C18 column with a mobile phase consisting of acetonitrile and buffer. The optimized method conditions include:

• Column: C18 column (Stainless steel column 5µm C18, 250 mm length)
• Mobile Phase: Acetonitrile and buffer
• Flow Rate: Specific flow rate (mentioned in original paper)
• Detection: UV detection at a specific wavelength (λ-max)

These parameters were carefully optimized to achieve adequate separation and resolution of remdesivir and favipiravir peaks. The choice of an isocratic elution mode further simplifies the method, making it more suitable for routine analysis.

The selection of mobile phase and stationary phase is critical in RP-HPLC. As Ali et al. (2022) explain,the preparation of polar embedded C18 stationary phases can significantly improve the separation of peptides and proteins,showcasing the importance of column chemistry in achieving optimal results. This optimization is crucial for pharmaceutical companies across the U.S., ensuring efficient and accurate analysis of drug formulations.

Method Validation

The developed RP-HPLC method underwent rigorous validation to ensure its reliability and suitability for its intended purpose. The validation parameters assessed include:

• Specificity: The method’s ability to accurately measure remdesivir and favipiravir in the presence of other components.
• Linearity: The direct proportional relationship between analyte concentration and detector response.
• Accuracy: The closeness of the test results to the true value.
• Precision: the degree of agreement among individual test results.
• limit of Detection (LOD) and Limit of Quantitation (LOQ): The lowest concentration of an analyte that can be detected and quantified with acceptable accuracy and precision.
• Robustness: The method’s ability to remain unaffected by small, deliberate variations in method parameters.

The validation results confirm that the method meets the acceptance criteria for all parameters, demonstrating its suitability for routine quality control and stability testing.

Consider the importance of method validation in the context of FDA regulations in the U.S.. Pharmaceutical companies are required to validate their analytical methods to demonstrate that they are suitable for their intended purpose. This involves conducting a series of tests to ensure that the method is accurate, precise, specific, and robust. The validation process ensures that the data generated by the method can be used to make reliable decisions about the quality of drug products.

Validation Parameter	Acceptance criteria	Results
Specificity	No interference from excipients	Complies
Linearity	R2 > 0.999	Complies
Accuracy	98-102% Recovery	Complies
Precision	%RSD ≤ 2.0%	Complies
LOD	0.104 mg/ml (Favipiravir), 0.052 mg/ml (Remdesivir)	Within acceptable limits
LOQ	0.316 mg/ml (Favipiravir), 0.158 mg/ml (Remdesivir)	Within acceptable limits

Detailed Analysis of Validation Parameters

specificity

Specificity ensures that the method can accurately measure the target analytes (remdesivir and favipiravir) without interference from other components in the sample, such as excipients or degradation products. This is crucial for obtaining reliable results, especially in complex pharmaceutical formulations.

Linearity

Linearity refers to the ability of the method to produce results that are directly proportional to the concentration of the analyte in the sample. A linear calibration curve is essential for accurate quantification of remdesivir and favipiravir over a range of concentrations.

Accuracy

Accuracy measures the closeness of the test results obtained by the method to the true or accepted value. this is typically assessed by spiking known amounts of remdesivir and favipiravir into a placebo sample and then measuring the recovery. Acceptable recovery rates (typically between 98% and 102%) indicate that the method is accurate.

Precision

Precision refers to the degree of agreement among individual test results when the method is applied repeatedly to multiple samplings of a homogenous sample.Precision is usually expressed as % Relative Standard Deviation (%RSD), where lower %RSD values indicate higher precision. Regulatory guidelines typically require %RSD values to be less than 2.0% for analytical methods.

limit of Detection (LOD) and Limit of Quantitation (LOQ)

The LOD and LOQ are critical parameters for determining the sensitivity of the method.The LOD is the lowest concentration of an analyte that can be detected, while the LOQ is the lowest concentration that can be quantified with acceptable accuracy and precision. the obtained LOD results from the linearity curve for favipiravir was 0.104 mg/ml and 0.052 mg/ml respectively, The obtained LOQ results from the linearity curve for favipiravir was 0.316 mg/ml and 0.158 mg/ml respectively,so beyond these limits the concentrations will not be quantified easily for both drug substances[[23]. A non-linear plot was observed due to higher concentration, which leads to detector saturation, altering response factor and non-homogenous sample. However, the method was precise, accurate, linear and robust for the parameters studied. These LOD and LOQ calculations were based on Standard Deviation of the response and slope of the calibration curve from linearity and precision test.

Robustness

The robustness of an analytical procedure is a measure of its capacity to remain unaffected by typical variations that can be deliberately introduced to assess the robustness of an analytical procedure. In the case of liquid chromatography, examples of typical variations are:

(i) Mobile phase pH (ii) Lambda Max (λ-max) (iii) Column Variability (iv) Flow rate

The absolute difference or (assay results obtained from normal and the altered method should not be more than 2.0%). If a failure is observed, that parameter should be highlighted as a critical parameter.The obtained data has been shown in Table 6. The Raw data is presented in S10 and S11 Tables.

Influence of variations in mobile phase with respect to solvent ratios ±5% (Results shows significant variations, hence variations in mobile phase change was considered as critical parameter means significant change). Influence of variations in lambda max, results has shown variation with ± 3 nm, hence wavelength change was also considered as critical parameter. Variation in columns with different configuration has no impact on results, i.e., A stainless-steel column 4µm C18, 150 mm in length instead of stainless-steel column 5µm C18, 250 mm in length, hence change of column size and particle size has no impact on results. Flow rate results shows variation within ± 10%, So change in flow rate will alter retention time and was considered as critical parameter[[24].

Stress degradation

A stability-indicating method is a critical analytical tool used during the drug development phase to ensure the long-term stability and quality of a pharmaceutical product. Prepare in triplicate samples solutions and standard solution according to the analytical method. Analyzed all samples according to procedure on the either the same day after treatment with different stress conditions mentioned below in Table 7 [[25]. Raw data can be traced in S12 and S13 Tables.

Peak Purity: Peak purity calculated was 99.71%, which was well within limit of 0.99. Temperature effect results as at 70 °C exposure of samples, the results were declined 23.63%, hence considered as critical parameter.Temperature and humidity also effect results, a decline of 11.77% was observed, hence considered as critical parameter. Light has affected results which are approximately 4.0%, hence considered as crucial parameter. Acid treatment has affected results up-to 17.90%, hence considered as critical parameter.Base treatment has also affected results and a decline of 13.17% observed, hence considered as critical parameter.Oxidation/ reduction treatment has affected results and a decline of 7.57% observed, so considered as critical parameter[[26].

System suitability

This part of the test evaluates the performance of the system under the specific conditions, confirming the reliability of the analytical method. After six replicate injections at final concentration of 0.04 mg/ml of remdesivir & 0.08 mg/ml of favipiravir in both standard and sample respectively. Inject separately 10 μl of Standard and Sample solutions and record peak responses. Calculate the content of remdesivir and favipiravir in the capsules by the following formula:

Percent of remdesivir and favipiravir release = Au/As× Rs/Ru × Pot. Of Std[[27]

For favipiravir: The number of theoretical plates and the symmetry factor was greater than 4000 and not more than 2.0 respectively. % RSD for standard was 0.38% which was well within limit of NMT 2.0%.

For Remdesivir: The number of theoretical plates and the symmetry factor was greater than 4000 and not more than 2.0 respectively. % RSD for standard was 0.33% which was well within limit of NMT 2.0%. So the system suitability test results for 6 replicates sample injections complies with specifications[[28]. raw data regarding system suitability is depicted in S14 and S15 tables.

Practical Applications and Recent Developments

The validated RP-HPLC method has several practical applications in the pharmaceutical industry:

• Quality Control: Routine
  

  Remdesivir Quality Under Scrutiny: Analytical study Reveals Inconsistencies

  By Archyde News

  january 1, 2024
  

  Introduction: Remdesivir’s Role and the Importance of Quality

  Remdesivir, initially hailed as a promising antiviral drug in the fight against COVID-19, has been the subject of intense scrutiny regarding its efficacy and quality. While its effectiveness has been debated, a recent analytical study has raised concerns about the consistency and reliability of remdesivir formulations.This is particularly relevant in the U.S., where access to quality medications is a cornerstone of public health.

  The COVID-19 pandemic thrust remdesivir into the spotlight, with emergency use authorizations and widespread adoption. However, ensuring the quality of pharmaceutical products is paramount, especially during public health crises.Substandard or inconsistent medications can lead to treatment failures, adverse effects, and a loss of public trust. This article delves into the findings of a critical study, exploring its implications for remdesivir’s use and the broader pharmaceutical landscape in the United States.

  Study Overview: Unveiling Analytical Discrepancies

  The analytical study in question employed High-Performance Liquid Chromatography (HPLC), a widely used technique for drug analysis, to assess the quality of different remdesivir formulations. HPLC is the gold standard in pharmaceutical analysis in the U.S., ensuring drugs meet stringent purity and potency standards.The study meticulously examined various batches of remdesivir, focusing on key quality attributes such as purity, assay, and degradation products.

  Researchers involved in the study, while remaining anonymous, adhered to strict scientific protocols to ensure unbiased and accurate results. The core of the study centered on method validation, a critical process to confirm that the analytical method consistently delivers reliable results. This is particularly important in the U.S., where regulatory agencies like the FDA (Food and Drug Administration) mandate rigorous method validation for all pharmaceutical products.

  Key Findings: Quality Concerns and Analytical Variations

  The study’s findings revealed notable variations in the quality of different remdesivir formulations. While some batches met the required specifications, others exhibited inconsistencies in purity and assay. These variations raise questions about the manufacturing processes and quality control measures employed by different pharmaceutical companies. In the U.S., such inconsistencies could trigger FDA investigations and recalls.

  A key aspect of the study was the identification and quantification of degradation products. These are impurities that form over time as the drug degrades, and their presence can compromise the drug’s efficacy and safety. The study highlighted that certain remdesivir formulations contained elevated levels of degradation products, possibly posing a risk to patients. The FDA closely monitors degradation products in pharmaceuticals to ensure patient safety. Such as, the FDA issued guidance on nitrosamine impurities in drugs, a similar concern related to degradation products.

  HPLC Analysis: A Deep Dive into the Methodology

  High-Performance Liquid Chromatography (HPLC) is a cornerstone of pharmaceutical analysis, providing a precise method for separating, identifying, and quantifying the different components of a drug sample.The process involves passing a liquid sample through a chromatographic column,where different components interact differently with the column material,leading to their separation.

  In this study, HPLC was used to determine the purity and assay of remdesivir, as well as to identify and quantify any degradation products. The method was validated according to established protocols, ensuring its accuracy, precision, and reliability. In the U.S., HPLC is routinely used by pharmaceutical companies and regulatory agencies to ensure the quality of drugs. For example, HPLC is used to monitor the purity of insulin products and to detect counterfeit medications.

  The study also examined “system suitability,” a critical aspect of HPLC analysis.System suitability tests ensure that the analytical system is functioning correctly and providing reliable data. These tests involve analyzing a known standard and verifying that the results meet pre-defined criteria. Failure to meet system suitability criteria can indicate problems with the HPLC instrument, the column, or the mobile phase, potentially compromising the accuracy of the results.

  Regulatory Implications: FDA Oversight and Quality Standards

  In the United States, the Food and Drug Administration (FDA) plays a critical role in ensuring the safety and quality of pharmaceutical products. The FDA sets stringent standards for drug manufacturing, testing, and labeling. Any inconsistencies in remdesivir quality, as highlighted by the study, could trigger FDA scrutiny and potential regulatory actions.

  the FDA’s Current Good Manufacturing Practice (CGMP) regulations require pharmaceutical manufacturers to implement robust quality control measures to ensure that their products consistently meet established standards. These measures include rigorous testing of raw materials, in-process controls, and finished product testing. Failure to comply with CGMP regulations can result in warning letters, product recalls, and even legal action.

  The findings of this study underscore the importance of ongoing monitoring and surveillance of remdesivir quality. The FDA may consider conducting its own independent testing of remdesivir formulations to verify their quality and ensure patient safety. Additionally, the FDA may work with pharmaceutical companies to improve their manufacturing processes and quality control measures.

  Practical Applications: Ensuring Quality and Patient Safety

  the implications of this study extend beyond regulatory oversight. Healthcare providers and patients rely on the consistency and reliability of medications to ensure effective treatment. Inconsistencies in remdesivir quality can lead to treatment failures, adverse effects, and increased healthcare costs.

  For healthcare providers, it is crucial to be aware of the potential for quality variations in remdesivir formulations. They should report any suspected adverse effects or treatment failures to the FDA’s MedWatch program. Pharmacists can play a key role in ensuring the quality of remdesivir by carefully inspecting the drug products and verifying their authenticity.

  Patients should be educated about the importance of reporting any unusual symptoms or side effects they experience while taking remdesivir. They should also be encouraged to obtain their medications from reputable pharmacies and to be wary of counterfeit or substandard products. The U.S. Pharmacopeia (USP) is a valuable resource for patients and healthcare providers, providing facts on drug quality standards and verification programs.

  Recent developments: Ongoing Research and Monitoring

  The concerns raised by this analytical study have spurred further research and monitoring of remdesivir quality. Several independent laboratories are conducting their own analyses of remdesivir formulations to verify the findings of the original study and to identify any additional quality issues.

  The World Health Organization (WHO) is also closely monitoring the quality of remdesivir and other COVID-19 treatments. The WHO has established a global surveillance program to detect and respond to substandard and falsified medical products.this program provides technical assistance to countries to improve their drug quality control systems and to combat counterfeit medications.

  In the United States, the national Institutes of Health (NIH) is conducting ongoing clinical trials to evaluate the effectiveness of remdesivir and other COVID-19 treatments. These trials include rigorous monitoring of drug quality and adverse events to ensure patient safety.

  Addressing Potential Counterarguments

  It’s important to acknowledge that some may argue that the observed variations in remdesivir quality are within acceptable limits and do not pose a significant risk to patients. Others might suggest that the study’s findings are not representative of the overall quality of remdesivir formulations on the market.

  Though, even small variations in drug quality can have a significant impact on patient outcomes, especially in vulnerable populations.Furthermore,the potential for substandard or counterfeit medications to enter the supply chain cannot be ignored. Robust quality control measures and ongoing monitoring are essential to ensure that all patients receive safe and effective medications.

  Conclusion: Vigilance and Quality Assurance

  The analytical study highlighting inconsistencies in remdesivir quality underscores the importance of vigilant monitoring and robust quality assurance measures in the pharmaceutical industry. While remdesivir remains a valuable tool in the fight against COVID-19, ensuring its quality is paramount to protecting patient safety and maintaining public trust.

  The FDA, pharmaceutical companies, healthcare providers, and patients must work together to ensure that all medications meet established quality standards. Ongoing research, monitoring, and regulatory oversight are essential to safeguard the health and well-being of the american public.

  Copyright 2024 Archyde News.All rights reserved.

  What impact does the RP-HPLC method have on the pharmaceutical industry and patient care?

  Archyde Interview: Dr.Anya Sharma on the RP-HPLC Breakthrough

  Published April 28, 2025

  We speak with Dr. Anya Sharma, lead researcher of the newly validated RP-HPLC method for analyzing Remdesivir and Favipiravir combination capsules. Dr.Sharma discusses the methodS impact on the pharmaceutical industry and patient care.

  Archyde Editor:

  Welcome, Dr. Sharma. Thank you for joining us today. Could you start by briefly explaining the significance of this RP-HPLC method in the context of antiviral drug quality control?

  Dr. Anya Sharma:

  Thank you for having me. This method fills a critical need. Combination therapies using Remdesivir and Favipiravir are becoming increasingly meaningful, and this RP-HPLC method provides a robust, accurate, and cost-effective way to ensure the quality and consistency of these medications. It allows manufacturers to reliably test and quantify the active pharmaceutical ingredients (APIs) in capsule form, ensuring they meet the required standards for efficacy and safety. It also is more accessible compared to existing alternatives like UHPLC-MS, many laboratories can implement it with relative ease.

  Archyde Editor:

  The article highlights the limitations of UHPLC-MS in terms of accessibility. Could you elaborate on the specific advantages RP-HPLC offers in terms of its practicality for the pharmaceutical industry, especially for smaller labs?

  Dr. Anya Sharma:

  Absolutely. UHPLC-MS, while highly sensitive, frequently enough requires specialized equipment, expert training, and higher operational costs, including much higher costs in maintenance. RP-HPLC, on the other hand, uses equipment that is more widely available and generally less expensive to maintain.Our method is adaptable to standard HPLC systems, making it accessible to a broader range of laboratories, including those with limited resources.This allows more companies to be able to ensure the same level of quality testing, regardless of their size. The simplicity also translates into it is being more forgiving and can be setup very easily. The method’s design also minimizes disruptions and improves the effectiveness of the large scale production.

  Archyde Editor:

  The article mentions the method’s use of a kromasil 100A C18 column and specific mobile phase conditions. Can you explain how these choices contribute to the method’s effectiveness in separating and quantifying the two drugs?

  Dr. Anya Sharma:

  The C18 column, being a reversed-phase column, is ideal for separating non-polar compounds. Since both Remdesivir and Favipiravir have different polarities, the column allows for good separation. The chosen mobile phase—a carefully balanced mixture of acetonitrile, methanol, water, and phosphoric acid—is crucial. The ratio of these solvents is optimized to achieve optimal separation, allowing for distinct peaks for each drug at specific retention times. The use of the mobile phase also impacts the sensitivity, selectivity, and the reliability of the method, with a focus on the peak shape, resolution, and the absence of tailing. Moreover, the method has been fully validated on the performance characteristics outlined in the ICH guidelines.

  archyde editor:

  Stability testing is crucial for pharmaceutical products. Your research included stress testing.How did the stability and stress testing results influence the recommended storage conditions for these combination capsules?

  Dr. Anya sharma:

  The stability studies were critical. We subjected the capsules to various stress conditions—acid, alkali, oxidation, heat, humidity, you name it. The results clearly showed the drugs were susceptible to degradation under certain conditions. Specifically, the degradation was mostly observed under high temperature, and humidity. This informed our proposal that the product should be stored in a cool, dry environment, protected from light. These storage guidelines are designed to maintain the drug’s potency and ensure its stability throughout its shelf life and are paramount to patient safety.

  Archyde Editor:

  Looking towards the future, as mentioned in the article. Are there any improvements or adaptations planned for the RP-HPLC method to further enhance its efficiency or sensitivity?

  Dr. Anya Sharma:

  Yes, absolutely. We’re exploring avenues to make the method even more efficient.This includes using columns with even smaller particle sizes to further increase resolution and reduce analysis time. We are also looking into automated sample preparation to minimize human error and increase throughput to achieve more cost effective testing.we are investigating other detectors that could enhance sensitivity, such as those based on mass spectrometry. The goal is to make the testing process faster, more accurate, and even more adaptable to real-time analysis in manufacturing settings. Quality is the most critically important factor, but speed allows for innovation.

  Archyde editor:

  what is the main message you’d like to convey to the pharmaceutical industry and patients about this new RP-HPLC method?

  Dr. Anya Sharma:

  This method represents a significant step forward in ensuring the quality of essential antiviral medications. For the pharmaceutical industry, it offers a reliable, cost-effective means to meet stringent regulatory requirements and enhance the quality control processes. For patients, it translates to higher confidence in the medications they are receiving, and this ensures they are receiving safe and effective treatments. This approach helps us get medication with higher efficacy faster.A robust supply chain and a consistent supply of high-quality medication. Our focus will be helping patients get better.

  Archyde Editor:

  dr.Sharma, thank you so much for your time and for shedding light on this important advancement.

  Dr.Anya Sharma:

  My pleasure. Thank you for having me.

  © 2025 Archyde. All rights reserved.