Development of a simple HPLC–UV method for the determination of the hepatitis C virus inhibitor simeprevir in human plasma

An environmentally sustainable synchronous spectrofluorimetric method coupled with second derivative signal processing for simultaneous determination of velpatasvir and simeprevir in pharmaceutical and plasma samples

Velpatasvir and simeprevir are two direct acting antivirals that are often used in combination with sofosbuvir to treat HCV infections. Herein, an environmentally benign spectrofluorimetric method was developed for simultaneous quantification of velpatasvir and simeprevir in pharmaceutical and plasma samples. To address the issue of overlapping fluorescence spectra presented by these compounds, this method integrates synchronous fluorescence and second-derivative spectroscopy. By employing the second derivative of the synchronous fluorescence spectra measured at Δλ of 140 nm, the accurate determination of velpatasvir at 400 nm and simeprevir at 426 nm was achieved without any interference. Different experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully optimized. The plots of second-derivative amplitudes against concentrations showed linearity in the range of 5-400 ng/mL for velpatasvir and 80-800 ng/mL for simeprevir. The method was very sensitive, with lower detection limits of 1.11 ng/mL and 25.40 ng/mL, and quantification limits of 3.36 ng/mL and 76.96 ng/mL for velpatasvir and simeprevir, respectively.The method was effectively used to determine velpatasvir and simeprevir simultaneously in their pure forms, pharmaceutical dosage forms, and human plasma with no interference. The suggested technique was additionally evaluated for its eco-friendliness through the utilization of the Analytical GREEnness (AGREE) and Green Analytical Procedure Index (GAPI) evaluation metrics, revealing that the method is indeed sustainable.

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.

Simultaneous spectrofluorimetic determination of remdesivir and simeprevir in human plasma

As new infectious mutations of SARS-CoV-2 emerged throughout the world, innovative therapies to counter the virus-altered drug sensitivities were urgently needed. Several antiviral options have been in clinical trials or in compassionate use for the treatment of SARS-CoV-2 infections in an attempt to minimize both clinical severity and viral shedding. Recent research indicated that simeprevir acts synergistically with remdesivir, allowing for a multiple-fold decrease in its effective dose when used at physiologically acceptable concentrations. The goal of this work is to develop a sensitive synchronous spectrofluorimetric approach to simultaneously quantify the two drugs in biological fluids. Using this method, remdesivir and simeprevir could be measured spectrofluorimetrically at 283 and 341 nm, respectively, without interference from each other using Δλ of 90 nm. The effect of various experimental parameters on the fluorescence intensity of the two drugs was extensively explored and optimized. For each of remdesivir and simeprevir, the method exhibited a linearity range of 0.10-1.10 μg/mL, with lower detection limits of 0.01 and 0.02 μg/mL and quantification limits of 0.03 and 0.05 μg/mL, respectively. The high sensitivity of the developed method permitted the simultaneous determination of both drugs in spiked plasma samples with % recoveries ranging from 95.0 to 103.25 with acceptable standard deviation values of 1.92 and 3.04 for remdesivir and simeprevir, respectively. The validation of the approach was approved by the International Council of Harmonization (ICH) guidelines.

Application of different spectrophotometric methods for quantitative analysis of direct acting antiviral drugs simeprevir and sofosbuvir

Simeprevir and sofosbuvir are direct-acting antiviral drugs approved for the treatment of chronic HCV infection. Reports demonstrate the similarities between HCV and SARS-CoV-2 in terms of structure and replication mechanism. Therefore, it is suggested that a combination of simeprevir and sofosbuvir may be considered for COVID-19 patients. To date, no spectrophotometric methods have been published for quantitative analysis of simeprevir and sofosbuvir in combination. In this work, two simple spectrophotometric methods allowed quantitative analysis of the studied drugs in the mixed form. The zero-order direct method allowed quantitative analysis of simeprevir at 333 nm, with sofosbuvir showing zero absorbance values. The dual wavelength method allowed quantitative analysis of sofosbuvir by measuring the difference in absorbance values at 259.40 and 276 nm, where the difference in absorbance values of simeprevir was zero. With the applied methods, the investigated drugs in the mixtures and tablets prepared in the laboratory were successfully analyzed quantitatively with acceptable results.

Feasible TLC-Spectro-Densitometry Technique for Simultaneous Determination of Two Hepatitis C Antiviral Drugs, Sofosbuvir and Simeprevir: Application to Combined Pharmaceutical Dosage Forms and Human Plasma

A high-performance thin-layer chromatographic method was developed and validated for the concurrent determination of simeprevir (SMV) and sofosbuvir (SOF). The chromatographic separation was attained on silica gel 60 F254 as stationary phase and ethyl acetate-hexane-methanol (5.0:4.0:1.0, v/v/v) as developing solvent with UV detection at 273 nm. The RF values were 0.67±0.02 and 0.43±0.02 for SMV and SOF, respectively. The method has been validated in respect to the guidelines of the International Conference on Harmonization. Linearity was maintained between 60-1,000 and 70-1,200 ng/band for SMV and SOF, respectively, with good correlation coefficients (0.9993-0.9997) for both drugs. The suggested method was highly sensitive as the calculated detection limits were 15 and 22 ng/band, while the quantitation limits were 44 and 66 ng/ band for SMV and SOF, respectively. The suggested methodology has been effectively employed for the determination of the mentioned drugs in their pure forms and their pharmaceutical dosage forms as well as human plasma without significant interference of the pharmaceutical excipients or plasma components.

Analytical Methods for Determination of Antiviral Drugs in Different Matrices: Recent Advances and Trends

Viruses are the main pathogenic substances that cause severe diseases in humans and other living things. They are among the most common microorganisms, and consequently, antiviral drugs have emerged to prevent and treat viral infections. Antiviral drugs are an essential drug group considering their prescription and consumption rates for different diseases and indications. Therefore, it is crucial to develop accurate and precise analytical methods to detect antiviral drugs in various matrices. Chromatographic techniques are used frequently for the quantification purpose since they allow simultaneous determination of antivirals. Electrochemical methods have also gained importance since the analysis can be performed quickly without the need for pretreatment. Spectrophotometric and spectrofluorimetric methods are used because they are simple, inexpensive, and less time-consuming methods. The purpose of this review is to present an overview of the analysis of currently used antiviral drugs from 2010 to 2021. Since studies on antiviral drugs are numerous, selected publications were reviewed in this article. The analysis of antiviral drugs was divided into three main groups: chromatographic, spectrometric, and electrochemical methods which were applied to different matrices, including pharmaceutical, biological, and environmental samples.

Insights into flibanserin oxidative stress degradation pathway: in silico – in vitro toxicity assessment of its degradates

Characterization of the degradation products of pharmaceutical drugs is essential to assess their safety.

Identification, isolation, structural characterization, in silico toxicity prediction and in vitro cytotoxicity assay of simeprevir acidic and oxidative degradation products

Simeprevir is a new direct-acting antiviral drug used for the treatment of chronic hepatitis C. In this work, a simple, fast and economical chromatographic method was developed for the determination of simeprevir in the presence of its acidic and oxidative degradation products. The stress studies performed herein showed that simeprevir degraded under acidic and oxidative conditions but was stable under thermal and alkaline conditions. Chromatographic separation was achieved on a reversed-phase Eclipse XDB C18 column (4.6 × 150 mm, 5 μm). The mobile phase consisted of methanol-0.05 M ammonium acetate (pH 4) (90 : 10, v/v) and was used at a flow rate of 1 mL min-1. The column effluent was monitored at 237 nm. The calibration curve was linear over the concentration range of 0.1-20 μg mL-1. The relative standard deviations for the intra-day and inter-day precision were less than 2%, and good percentage recoveries that met the acceptance criteria of the International Conference on Harmonization (ICH) guidelines were obtained. The robustness was assessed using the Plackett-Burman design. The simeprevir degradation products were isolated by flash chromatography and confirmed by 1H NMR and LC-MS/MS techniques. The fully validated chromatographic method can be applied as a stability-indicating method for simeprevir and for routine analysis during quality control. Additionally, in silico toxicity prediction of the degradation products demonstrated a hepatotoxicity alert for DP 1, DP 2, DP 4 and DP 5 and a carcinogenicity alert for DP 3. In view of safety aspects, an in vitro cytotoxicity assay was carried out for simeprevir degradation products. They were found to be non-toxic in vitro at the tested concentrations.

Development and Greenness Evaluation of Spectrofluorometric Methods for Flibanserin Determination in Dosage Form and Human Urine Samples

Green, economic and sensitive two spectrofluorometric methods were developed for the quantitation of flibanserin (FB) in different matrices, which are based on FB native fluorescence properties. The first technique depends on measuring the relative fluorescence intensity of FB directly at emission and excitation wavelengths(λ_em/λ_ex) (371 nm/247 nm), while the second technique is a first derivative (D¹) spectrofluorometric method, which depends on measuring the peak amplitudes at 351 nm. Linear regressions were observed in the range of 0.1–1.5 μg/mL for both methods. Moreover, both methods were efficiently extended to analyze FB in human urine, indicating the ultra-sensitivity of the methods, and linear regression was found within a range 0.05–0.7 μg/mL for both methods. Excellent selectivity of the proposed methods and good recoveries were obtained upon the analysis of FB in pharmaceutical dosage form and human urine samples without interference from matrix components with acceptable ranges, from 98.86 to 101.46% and from 98.08 to 102.37%, respectively. Greenness of the developed methods was assessed using the national environmental method index (NEMI) and Analytical Eco-scale and Green Analytical Procedure Index (GAPI). The three approaches confirmed that the developed methods are green, safe and environment-friendly.

Validated Reversed-Phase Liquid Chromatographic Method with Gradient Elution for Simultaneous Determination of the Antiviral Agents: Sofosbuvir, Ledipasvir, Daclatasvir, and Simeprevir in Their Dosage Forms

A simple, rapid, sensitive, and precise reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of four direct-acting antivirals, sofosbuvir (SF), ledipasvir (LD), declatasvir (DC), and simeprevir (SM), in their respective pharmaceutical formulations. Effective chromatographic separation was achieved on an Agilent Eclipse plus C8 column (250 mm × 4.6 mm, 5 µm) at 40 °C with gradient elution using a mobile phase composed of acetonitrile:phosphate buffer (pH 6.5). The quantification of SF and DC was based on peak area measurements at 260 nm, while the quantification of LD and SM was achieved at 330 nm. The linearity was acceptable from 1.0 to 20.0 μg/mL for the studied drugs, with correlation coefficients >0.999. The analytical performance of the newly proposed HPLC procedure was thoroughly validated according to ICH guidelines in terms of linearity, precision (RSD%, 0.39-1.57), accuracy (98.05-101.90%), specificity, limit of detection (LOD) (0.022-0.039 μg/mL), limit of quantification (LOQ) (0.067-0.118 μg/mL), and robustness. The validated HPLC method was successfully used to analyze the abovementioned drugs in their pure and dosage forms without interference from common excipients present in commercial formulations.

Micelle sensitized synchronous spectrofluorimetric approaches for the simultaneous determination of simeprevir and ledipasvir: Application to pharmaceutical formulations and human plasma

Simeprevir (SMV) is commonly co-administered with ledipasvir (LDS) and sofosbuvir (SOF) as an effective combination regimen for treatment naive hepatitis C virus infected patients. In the present study, two spectrofluorimetric approaches were combined together for the development of highly sensitive, rapid, simple and accurate method for simultaneous quantification of SMV and LDS. The native fluorescence intensity values of SMV and LDS were enhanced by the addition of Tween-80 micellar system, while second derivative of the synchronous fluorescence intensity of the drugs at Δλ = 120 nm enabled the determination of both drug concomitantly. Different experimental parameters affecting the synchronous fluorescence of the cited drugs were carefully evaluated for their optimization. The peak amplitudes of the second derivative synchronous fluorimetry were measured at 429 nm for SMV and at 417 nm for LDS. The fluorescence-concentration plots were rectilinear over the range of 60-1500 and 36-540 ng mL^-1 with lower detection limits of 9.0 and 6.0 ng mL^-1 and quantification limits of 27.0 and 17.0 ng mL^-1 for SMV and LDS respectively. The method was successfully applied for the determination of both drugs in their pure forms as well as their pharmaceutical products and human plasma without any significant interference. Statistical comparison with the reported method revealed excellent accuracy and precision of the proposed method.

Stress stability study of simeprevir, a hepatitis C virus inhibitor, using feasible TLC-spectro-densitometry: application to pharmaceutical dosage form and human plasma

Simeprevir is one of the newest direct action anti-hepatitis C drugs. In the present work, a simple, highly selective and stability-indicating, high-performance thin-layer chromatography (HPTLC) method is proposed and validated for the assay of simeprevir both in pharmaceutical dosage form and spiked human plasma. The method used silica gel 60 F254 coated HPTLC aluminum plates as the stationary phase. The mobile phase system was ethyl acetate-hexane-methanol (5 : 4 : 1, v/v/v). The wavelength for both detection and quantitation was set at 288 nm. This system was found to give a compact spot of simeprevir; the retardation factor (R F) value was 0.67 ± 0.02. The guidelines of the International Conference on Harmonization were followed to validate the proposed analytical method, and the results were acceptable. The calibration curve was linear over the range of 80-1000 ng per spot. The limit of detection was 19.0 ng per spot, and the limit of quantitation was 57.0 ng per spot. The drug was subjected to various stress conditions including hydrolytic, oxidative and UV-induced resulting in varying degrees of degradation. The results showed that the proposed method could efficiently separate the degradation products from the intact drug and allow its satisfactory quantitation. The proposed method was employed successfully for the accurate and reproducible analysis of the pharmaceutical preparation and human plasma containing the drug. The proposed method's precision and accuracy were statistically similar to those of a reported method.

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

Background:

Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe.

Objective:

The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma.

Methods:

Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard.

Results:

Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals.

Conclusion:

This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

Microenvironment improvement protocol for the sensitive spectrofluorimetric determination of an hepatitis C virus antiviral (Simeprevir): application to human plasma

Simeprevir (SPV) is a powerful antihepatitis C virus agent that was newly introduced into the pharmaceutical market. We here established and validated an easy, simple, and sensitive spectrofluorimetric method for its estimation at λ_em 427 nm (λ_ex 337 nm). The suggested procedure was based on two times enhancement in the original emission of SPV through modifying its microenvironment in buffered aqueous solution by adding Triton X-100. The relationship between the concentration of SPV and the observed fluorescence intensity was linear in the range 0.06-1.0 μg ml^-1 with a correlation coefficient of 0.9997. The limits of detection and quantitation were 21 and 64 ng ml^-1 , respectively. The present method was effectively applied to quantify SPV content in pharmaceutical tablets and human plasma spiked with the drug with no interference from tablet excipients or plasma components.

Simultaneous quantification of simeprevir sodium: A hepatitis C protease inhibitor in binary and ternary mixtures with sofosbuvir and/or ledipasvir utilizing direct and H-point standard addition strategies

Simeprevir sodium (SMV); a novel hepatitis C inhibitor, quells hepatitis C viral replication by binding to and repressing the protease, hepatitis C infection (HCV) NS3/4A. In this way, it is known as a prompt acting antiviral agent. Calibration curves of SMV were built in various solvents; ethanol, methanol, acetonitrile, chloroform and dichloromethane. It is obeyed up to 60.0 μg/mL; in all solvents at two maximum wavelengths (280 and 327 nm). Several investigations show that, SMV might be present in a mixture of Sofosbuvir (SOF) and/or Ledipasvir (LDP). So far as that is concerned, H-point standard addition strategy (HPSAS) is made to identify it in binary or ternary mixtures. Recovery studies are in the prevalent range (93.0-107.0%) with relative standard deviation <1.5%. A correlation between the developed techniques is carried out and it demonstrates that these strategies are effectively applied for the simultaneous analysis of SMV, SOF and LDP in several synthetic samples and pharmaceutics. Statistical treatment of the acquired data is carried out against a newly published HPLC technique using F- and t-treatments.

A sensitive and validated HPLC-UV method for the quantitative determination of the new antifungal drug isavuconazole in human plasma

Isavuconazole is a broad-spectrum triazole antifungal drug recently approved for the therapy of both invasive aspergillosis and mucormycosis. To support a widespread therapeutic drug monitoring of isavuconazole, a simple, sensitive, and precise high-performance liquid chromatography method with UV detection was developed and fully validated for the quantification of this drug in human plasma. The method involved a combined protein precipitation-solid-phase extraction and a chromatographic separation on a Waters XTerra RP₁₈ (150 × 4.6 mm, 3.5 μm) column using an isocratic mobile phase of ammonium acetate buffer (pH 8.0, 10 mm) and acetonitrile (45:55, v/v). The UV detection was performed at 285 nm. This method was linear (correlation coefficients ≥0.998), specific (no interference with plasma components or various potentially co-administrated drugs), sensitive (lower limit of quantification of 0.025 μg/mL), reproducible (coefficients of variation were ≤7.9%) and accurate (deviations ranged from -5.0 to 8.0%) over the range of 0.025-10 μg/mL. The method fulfilled all of the US Food and Drug Administration guidelines validation criteria and performed well in an international proficiency testing program. The assay was also successfully applied to routine therapeutic drug monitoring of patients and to drug stability investigations under various conditions.

Different spectrophotometric methods applied for the analysis of simeprevir in the presence of its oxidative degradation product: Acomparative study

Five simple spectrophotometric methods were developed for the determination of simeprevir in the presence of its oxidative degradation product namely, ratio difference, mean centering, derivative ratio using the Savitsky-Golay filters, second derivative and continuous wavelet transform. These methods are linear in the range of 2.5-40μg/mL and validated according to the ICH guidelines. The obtained results of accuracy, repeatability and precision were found to be within the acceptable limits. The specificity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. Furthermore, these methods were statistically comparable to RP-HPLC method and good results were obtained. So, they can be used for the routine analysis of simeprevir in quality-control laboratories.

Comparison between core-shell and totally porous particle stationary phases for fast and green LC determination of five hepatitis-C antiviral drugs

The performances of core-shell 2.7 μm and fully porous sub-2 μm particles packed in narrow diameter columns were compared under the same chromatographic conditions. The stationary phases were compared for fast separation and determination of five new antiviral drugs; daclatasvir, sofosbuvir, velpatasvir, simeprevir, and ledipasvir. The gradient elution was done using ethanol as green organic modifier, which is more environmentally friendly. Although both columns provided very good resolution of the five drugs, core-shell particles had proven to be of better efficiency. Under gradient elution conditions, core-shell particles exhibited faster elution, better peak shape, and enhanced resolution adding to lower system backpressure. The column backpressure on sub-2 μm particles was more than twice that on core-shell particles. This gives a chance to use conventional high-performance liquid chromatography conditions without needing special instrumentation as that required for ultra-high performance liquid chromatography. The method was validated for determination of the five drugs by gradient elution using mobile phase composed of organic modifier ethanol and aqueous part containing 0.75 g sodium octane sufonate and 3.0 g sodium dihydrogen phosphate per liter at pH of 6.15. Detection was done using UV-detector set at 210 nm. The linearity, accuracy, and precision were found very good within the concentration range of 2-200 μg/mL.

Bioanalytical methods for the detection of antidiabetic drugs: a review

Type 2 diabetes mellitus, a disease which prevalence has been progressively increasing worldwide, is characterized by chronic hyperglycemia resulting from the combination of inappropriate insulin secretion and/or resistance to insulin action. If left uncontrolled, diabetes is associated with complications such as dysfunction and failure of various organs, and even premature death. Along with lifestyle-modification strategies, several classes of oral antidiabetic agents can be employed for glycemic control. Thus, therapeutic drug monitoring of these drugs is essential to maintain appropriate treatment. This review discusses the most frequently employed analytical techniques and sample preparation systems to obtain a reliable and trustworthy method to quantify antidiabetic drugs in biological matrices. An adequate choice of internal standard, ideal chromatography conditions and most suitable analytical detector are reported.

Potential of RP-UHPLC-DAD-MS for the qualitative and quantitative analysis of sofosbuvir in film coated tablets and profiling degradants

Sofosbuvir is one of the new direct-acting antiviral drugs against hepatitis C virus (HCV) infection. This drug has recently been launched into the market, and generic versions of the medication are expected to be produced by local drug producers in some countries. Therefore, new methods are required to control sofosbuvir in pharmaceuticals. In the present study, a new method based on reversed phase (RP)-ultra-high performance liquid chromatography (UHPLC) coupled to diode array detection (DAD) and mass spectrometry (MS) was developed to facilitate the qualitative and quantitative analysis of sofosbuvir in film coated tablets. A wavelength of 260 nm was selected to perform a cost-effective quantification and the method showed adequate linearity, with an R2 value of 0.9998, and acceptable values of accuracy (75%-102%) and precision (residual standard deviation <5%). The detection and quantification limits were 0.07 μg/mL and 0.36 μg/mL, respectively. Furthermore, the use of high-resolution MS enabled us to ensure the specificity, check impurities and better sensitivity. Therefore, this methodology promises to be suitable not only for the routine analysis of sofosbuvir in pharmaceutical dosage forms, but also for potential degradants.

Current antiviral drugs and their analysis in biological materials - Part II: Antivirals against hepatitis and HIV viruses

This review is a Part II of the series aiming to provide comprehensive overview of currently used antiviral drugs and to show modern approaches to their analysis. While in the Part I antivirals against herpes viruses and antivirals against respiratory viruses were addressed, this part concerns antivirals against hepatitis viruses (B and C) and human immunodeficiency virus (HIV). Many novel antivirals against hepatitis C virus (HCV) and HIV have been introduced into the clinical practice over the last decade. The recent broadening portfolio of these groups of antivirals is reflected in increasing number of developed analytical methods required to meet the needs of clinical terrain. Part II summarizes the mechanisms of action of antivirals against hepatitis B virus (HBV), HCV, and HIV, their use in clinical practice, and analytical methods for individual classes. It also provides expert opinion on state of art in the field of bioanalysis of these drugs. Analytical methods reflect novelty of these chemical structures and use by far the most current approaches, such as simple and high-throughput sample preparation and fast separation, often by means of UHPLC-MS/MS. Proper method validation based on requirements of bioanalytical guidelines is an inherent part of the developed methods.