A fruitful century for the scalable synthesis and reactions of biphenyl derivatives: applications and biological aspects

This review provides recent developments in the current status and latest synthetic methodologies of biphenyl derivatives. Furthermore, this review investigates detailed discussions of several metalated chemical reactions related to biphenyl scaffolds such as Wurtz-Fittig, Ullmann, Bennett-Turner, Negishi, Kumada, Stille, Suzuki-Miyaura, Friedel-Crafts, cyanation, amination, and various electrophilic substitution reactions supported by their mechanistic pathways. Furthermore, the preconditions required for the existence of axial chirality in biaryl compounds are discussed. Furthermore, atropisomerism as a type of axial chirality in biphenyl molecules is discussed. Additionally, this review covers a wide range of biological and medicinal applications of the synthesized compounds involving patented approaches in the last decade corresponding to investigating the crucial role of the biphenyl structures in APIs.

Cyclic Voltammetry of Screen-Printed Carbon Electrode Coated with Ag-ZnO Nanoparticles in Chitosan Matrix

In this paper, the authors describe the fabrication of nanocomposite chitosan-based systems of zinc oxide (ZnO), silver (Ag) and Ag-ZnO. Recently, the development of coated screen-printed electrodes using metal and metal oxide nanoparticles (NPs) for the specific detection and monitoring of different cancer tumors has been obtaining important results. Ag, ZnO NPs and Ag-ZnO prepared by the hydrolysis of zinc acetate blended with a chitosan (CS) matrix were used for the surface modification of screen-printed carbon electrodes (SPCEs) in order to analyze the electrochemical behavior of the typical redox system of a 10 mM potassium ferrocyanide-0.1 M buffer solution (BS). The solutions of CS, ZnO/CS, Ag/CS and Ag-ZnO/CS were prepared in order to modify the carbon electrode surface, and were measured at different scan rates from 0.02 V/s to 0.7 V/s by cyclic voltammetry. The cyclic voltammetry (CV) was performed on a house-built potentiostat (HBP). The cyclic voltammetry of the measured electrodes showed the influence of varying the scan rate. The variation of the scan rate has an influence on the intensity of the anodic and cathodic peak. Both values of currents (anodic and cathodic currents) have higher values for 0.1 V/s (Ia = 22 μA and Ic = -25 μA) compared to the values for 0.06 V/s (Ia = 10 μA and Ic = -14 μA). The CS, ZnO/CS, Ag/CS and Ag-ZnO/CS solutions were characterized using a field emission scanning electron microscopy (FE-SEM) with EDX elemental analysis. The modified coated surfaces of screen-printed electrodes were analyzed using optical microscopy (OM). The present coated carbon electrodes showed a different waveform compared to the voltage applied to the working electrode, depending on the scan rate and chemical composition of the modified electrodes.

Recent trends in carbon nanotube (CNT)-based biosensors for the fast and sensitive detection of human viruses: a critical review

The current COVID-19 pandemic, with its numerous variants including Omicron which is 50-70% more transmissible than the previously dominant Delta variant, demands a fast, robust, cheap, and easily deployed identification strategy to reduce the chain of transmission, for which biosensors have been shown as a feasible solution at the laboratory scale. The use of nanomaterials has significantly enhanced the performance of biosensors, and the addition of CNTs has increased detection capabilities to an unrivaled level. Among the various CNT-based detection systems, CNT-based field-effect transistors possess ultra-sensitivity and low-noise detection capacity, allowing for immediate analyte determination even in the presence of limited analyte concentrations, which would be typical of early infection stages. Recently, CNT field-effect transistor-type biosensors have been successfully used in the fast diagnosis of COVID-19, which has increased research and commercial interest in exploiting current developments of CNT field-effect transistors. Recent progress in the design and deployment of CNT-based biosensors for viral monitoring are covered in this paper, as are the remaining obstacles and prospects. This work also highlights the enormous potential for synergistic effects of CNTs used in combination with other nanomaterials for viral detection.

Advances of Cobalt Nanomaterials as Anti-Infection Agents, Drug Carriers, and Immunomodulators for Potential Infectious Disease Treatment

Infectious diseases remain the most serious public health issue, which requires the development of more effective strategies for infectious control. As a kind of ultra-trace element, cobalt is essential to the metabolism of different organisms. In recent decades, nanotechnology has attracted increasing attention worldwide due to its wide application in different areas, including medicine. Based on the important biological roles of cobalt, cobalt nanomaterials have recently been widely developed for their attractive biomedical applications. With advantages such as low costs in preparation, hypotoxicity, photothermal conversion abilities, and high drug loading ability, cobalt nanomaterials have been proven to show promising potential in anticancer and anti-infection treatment. In this review, we summarize the characters of cobalt nanomaterials, followed by the advances in their biological functions and mechanisms. More importantly, we emphatically discuss the potential of cobalt nanomaterials as anti-infectious agents, drug carriers, and immunomodulators for anti-infection treatments, which might be helpful to facilitate progress in future research of anti-infection therapy.

Rapid diagnosis of COVID-19 via nano-biosensor-implemented biomedical utilization: a systematic review

The novel human coronavirus pandemic is one of the most significant occurrences in human civilization. The rapid proliferation and mutation of Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) have created an exceedingly challenging situation throughout the world's healthcare systems ranging from underdeveloped countries to super-developed countries. The disease is generally recognized as coronavirus disease 2019 (COVID-19), and it is caused by a new human CoV, which has put mankind in jeopardy. COVID-19 is death-dealing and affects people of all ages, including the elderly and middle-aged people, children, infants, persons with co-morbidities, and immunocompromised patients. Moreover, multiple SARS-CoV-2 variants have evolved as a result of genetic alteration. Some variants cause severe symptoms in patients, while others cause an unusually high infection rate, and yet others cause extremely severe symptoms as well as a high infection rate. Contrasting with a previous epidemic, COVID-19 is more contagious since the spike protein of SARS-CoV-2 demonstrates profuse affection to angiotensin-converting enzyme II (ACE2) that is copiously expressed on the surface of human lung cells. Since the estimation and tracking of viral loads are essential for determining the infection stage and recovery duration, a quick, accurate, easy, cheap, and versatile diagnostic tool is critical for managing COVID-19, as well as for outbreak control. Currently, Reverse Transcription Polymerase Chain Reaction (RT-PCR) testing is the most often utilized approach for COVID-19 diagnosis, while Computed Tomography (CT) scans of the chest are used to assess the disease's stages. However, the RT-PCR method is non-portable, tedious, and laborious, and the latter is not capable of detecting the preliminary stage of infection. In these circumstances, nano-biosensors can play an important role to deliver point-of-care diagnosis for a variety of disorders including a wide variety of viral infections rapidly, economically, precisely, and accurately. New technologies are being developed to overcome the drawbacks of the current methods. Nano-biosensors comprise bioreceptors with electrochemical, optical, or FET-based transduction for the specific detection of biomarkers. Different types of organic-inorganic nanomaterials have been incorporated for designing, fabricating, and improving the performance and analytical ability of sensors by increasing sensitivity, adsorption, and biocompatibility. The particular focus of this review is to carry out a systematic study of the status and perspectives of synthetic routes for nano-biosensors, including their background, composition, fabrication processes, and prospective applications in the diagnosis of COVID-19.

Electro-oxidation of amino-functionalized multiwalled carbon nanotubes

We report the electrochemistry of amino-functionalized multiwalled carbon nanotubes (MWCNTs-NH2) in the pH range from 0.3 to 6.4 using quantitative cyclic voltammetry (CV) and single entity electrochemistry measurements, making comparison with non-functionalized MWCNTs. CV showed the latter to both catalyze the solvent (water) decomposition and to undergo irreversible electro-oxidation forming oxygen containing surface functionality. The MWCNTs-NH2 additionally undergo an irreversible oxidation to an extent which is dependent on the pH of the solution, reflecting the variable amount of deprotonated amino groups present as a function of pH. Nano-impact experiments conducted at the single particle level confirmed the oxidation of both types of MWCNTs, showing agreement with the CV. The pK a of the amino groups in MWCNTs was determined via both electrochemical methods giving consistent values of ca. 2.5.

Nanobioengineering: A promising approach for early detection of COVID-19

Unique pneumonia due to an unknown source emerged in December 2019 in the city of Wuhan, China. Consequently, the World Health Organization (WHO) declared this condition as a new coronavirus disease-19 also known as COVID-19 on February 11, 2020, which on March 13, 2020 was declared as a pandemic. The virus that causes COVID-19 was found to have a similar genome (80% similarity) with the previously known acute respiratory syndrome also known as SARS-CoV. The novel virus was later named Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 falls in the family of Coronaviridae which is further divided into Nidovirales and another subfamily called Orthocoronavirinae. The four generations of the coronaviruses belongs to the Orthocoronavirinae family that consists of alpha, beta, gamma and delta coronavirus which are denoted as α-CoV, β-CoV, γ-CoV, δ-CoV respectively. The α-CoV and β-CoVs are mainly known to infect mammals whereas γ-CoV and δ-CoV are generally found in birds. The β-CoVs also comprise of SARS-CoV and also include another virus that was found in the Middle East called the Middle East respiratory syndrome virus (MERS-CoV) and the cause of current pandemic SARS-CoV-2. These viruses initially cause the development of pneumonia in the patients and further development of a severe case of acute respiratory distress syndrome (ARDS) and other related symptoms that can be fatal leading to death.

Role of nanotechnology in facing SARS-CoV-2 pandemic: Solving crux of the matter with a hopeful arrow in the quiver

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-sense single-stranded RNA virus species with a zoonotic origin and responsible for the coronavirus disease 2019(COVID-19). This novel virus has an extremely high infectious rate, which occurs through the contact of contaminated surfaces and also by cough, sneeze, hand-to-mouth-to-eye contact with an affected person. The progression of infection, which goes beyond complications of pneumonia to affecting other physiological functions which cause gastrointestinal, Renal, and neurological complication makes this a life threatening condition. Intense efforts are going across the scientific community in elucidating various aspects of this virus, such as understanding the pathophysiology of the disease, molecular biology, and cellular pathways of viral replication. We hope that nanotechnology and material science can provide a significant contribution to tackle this problem through both diagnostic and therapeutic strategies. But the area is still in the budding phase, which needs urgent and significant attention. This review provides a brief idea regarding the various nanotechnological approaches reported for managing COVID-19 infection. The nanomaterials recently said to have good antiviral activities like Carbon nanotubes (CNTs) and quantum dots (QDs) were also discussed since they are also in the emerging stage of attaining research interest regarding antiviral applications.

Three Smart and Original Spectrophotometric Data Processing Ratio Techniques for Resolving the Partial Overlapped Spectra of the Binary Antiviral Mixture Daclatasvir/Sofosbuvir: Application to Combined Dosage Form Darvoni® Tablets

BACKGROUND

The combination of Daclatasvir (DCV) and sofosbuvir (SFV) is now widely used as an ideal treatment for hepatitis C virus infection. For this purpose, simple, sensitive, rapid and smart spectrophotometric methods were developed and validated for the determination of these drugs in their combined dosage form.

OBJECTIVE

Development οf smart, sensitive, cheap spectrοphοtοmetric methοds fοr determinatiοn (DCV) and (SFV) in their combined dosage.

METHODS

Ratio subtraction (RS) and amplitude modulation (AM) and mean centering spectrophotometric methods were established and validated for the estimation of sofosbuvir (SFV) in existence of daclatasvir without previous separation, utilizing unified regression equation.

RESULTS

A linearity limit of 2.5-25.0 µg/mL was confirmed for the direct measurement of daclatasvir at 316 nm (because there is no interference from sofosbuvir). Linearity was confirmed over a concentration limit of 10.0-80.0 µg/mL for sofosbuvir. The current methods were established as stated by the ICH recommendations and by testing synthetic mixtures of both drugs, the specificity was examined. They were tested on their tablet dosage form and good recovery was obtained.

CONCLUSIONS

The current methods were tested on their tablet dosage form and good recovery was obtained. A statistical study has been established among the current ratio approaches and a published methods and there was no apparent statistical variation was obtained.

HIGHLIGHTS

Both antiviral agents can be quantified in existence of each other by the current methods, which is a great time and cost-saving valor of the developed methods. This valor is even more important in the case of the combined dosage form (Darvoni® tablets) to the pharmaceutical market.

A Novel Electrochemical Sensor Based on Reduced Graphene Oxide–TiO2 Nanocomposites with High Selectivity for the Determination of Hydroxychloroquine

A simply sensitive sensor based on a reduced graphene oxide–TiO₂ nanocomposite modified glassy carbon electrode (RGO–TiO₂/GCE) was developed for the electrochemical determination of an antimalarial drug, hydroxychloroquine (HCQ). The modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Electrochemical test showed that the RGO–TiO₂ electrode had stronger electrochemical activity and higher effective real surface area than that of TiO₂ electrode and bare electrode. The electrochemical response of RGO–TiO₂ nanocomposite modified electrode toward HCQ oxidation was studied by CV, chronoamperometry (CHA), chronocoulometry (CHC) and square-wave voltammetry (SWV). Interestingly, RGO–TiO₂/GCE indicated an excellent electrocatalytic activity for HCQ. Under the optimal experimental conditions, a linear relationship between the peak current and the concentration was obtained, ranging from 0.25 to 500 μM, with the detection limit (S/N = 3) of 12.5 nM and quantification limit (S/N = 10) of 0.97 μM. Furthermore, the proposed sensor was successfully applied to the determination of HCQ in pharmaceutical (tablets) samples. In summary, the developed sensor was low cost and efficient, making it potentially attractive for practical sample analysis application of HCQ.

HPLC-UV and TLC-Densitometry Methods for Simultaneous Determination of Sofosbuvir and Daclatasvir: Application to Darvoni® Tablet

Sofosbuvir and daclatasvir are co-formulated as directly acting antiviral agents used for treatment of hepatitis C virus. Two chromatographic methods were developed for their determination; the first one is an Reversed phase-high performance liquid chromatography (RP-HPLC) method, in which the separation was performed on C8 Zorbax® SB column (4.6 × 250 mm, 5 μm) using acetonitrile:water:0.05 M phosphate buffer, pH = 8 (50:45:5, v/v/v) as a mobile phase, and ultraviolet detection was performed at 280 nm. Good resolution was obtained, and linearity was confirmed in the range of 10-100 μg/mL for both drugs. The second method is Thin layer chromatography (TLC)-densitometric one, in which sofosbuvir and daclatasvir were separated on silica gel plates using ethyl acetate:hexane:methanol (9:0.5:0.5, v/v/v) as a developing system and the scanning wavelength was 280 nm. Linearity was confirmed over a concentration range of 0.4-25.4 μg/band for sofosbuvir, whereas for daclatasvir linearity scanning was in the range of 0.4-12.8 μg/band. Both antiviral agents can be quantified simultaneously in one analytical run, which is a great time- and cost-saving valor of the developed methods. This valor is even more important in the case of the combined dosage form (Darvoni® tablets) to the pharmaceutical market.

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.

Facile one pot sonochemical synthesis of layered nanostructure of ZnS NPs/rGO nanosheets for simultaneous analysis of daclatasvir and hydroxychloroquine

In this study, zinc sulfide nanoparticles were loaded on reduced graphene oxide (ZnS NPs/rGO) using simple sonochemical method. The nanocomposite was characterized using different morphological and electrochemical techniques such as TEM, SEM, PXRD, EDX, Raman spectroscopy, FTIR, N₂-adsorption-desorption, CV, and EIS. The ZnS NPs/rGO modified glassy carbon electrode (GCE) was used to simultaneously estimate hydroxychloroquine (HCQ) and daclatasvir (DAC) in a binary mixture for the first time. The modified nanocomposite exhibited good catalytic activity towards HCQ and DAC detection. In addition, it showed higher sensitivity, good selectivity and stability; and high reproducibility towards HCQ and DAC analysis. The activity of the modified electrode was noticeably improved due to synergism between ZnS NPs and rGO. Under optimum conditions of DPV measurements, the anodic peak currents (Ipa) were obviously increased with the increase of HCQ and DAC amounts with linear ranges of 5.0-65.0 and 7.0-65.0 nM with LODs of 0.456 and 0.498 nM for HCQ and DAC, respectively. The ZnS NPs/ rGO modified GCE was used to quantify HCQ and DAC in biological fluids with recoveries of 98.7-102.7% and 96.9-104.5% and RSDs of 1.89-3.57% and 1.91-3.70%, respectively.

Rapid diagnostics of coronavirus disease 2019 in early stages using nanobiosensors: Challenges and opportunities

The rapid outbreak of coronavirus disease 2019 (COVID-19) around the world is a tragic and shocking event that demonstrates the unpreparedness of humans to develop quick diagnostic platforms for novel infectious diseases. In fact, statistical reports of diagnostic tools show that their accuracy, specificity and sensitivity in the detection of COVID hampered by some challenges that can be eliminated by using nanoparticles (NPs). In this study, we aimed to present an overview on the most important ways to diagnose different kinds of viruses followed by the introduction of nanobiosensors. Afterward, some methods of COVID-19 detection such as imaging, laboratory and kit-based diagnostic tests are surveyed. Furthermore, nucleic acids/protein- and immunoglobulin (Ig)-based nanobiosensors for the COVID-19 detection infection are reviewed. Finally, current challenges and future perspective for the development of diagnostic or monitoring technologies in the control of COVID-19 are discussed to persuade the scientists in advancing their technologies beyond imagination. In conclusion, it can be deduced that as rapid COVID-19 detection infection can play a vital role in disease control and treatment, this review may be of great help for controlling the COVID-19 outbreak by providing some necessary information for the development of portable, accurate, selectable and simple nanobiosensors.

Chitosan/carbon nanotube hybrids: recent progress and achievements for industrial applications

This review focuses on the state-of-the-art of the recent research development on chitosan/CNT nanomaterials in biomedicine, (bio)sensors, and pollution management.

COVID-19 diagnostic approaches: different roads to the same destination

"SARS-CoV2", a previously unknown strain of coronaviruses caused a severe respiratory disease called Coronavirus disease (COVID-19) which emerged from Wuhan city of China on 30 December 2019, and declared as Global health problem by World Health Organisation within a month. In less than two and half months (11 March, 2020) it was declared as a pandemic disease due to its rapid spreading ability, it covered more than 211 countries infecting around 1.7 million persons and claiming around 1.1 lakhs lives within merely 100 days of its emergence. Containment of the infection of this virus is the only available measure to control the disease as no vaccine or specific antiviral treatment is available. Confirmed detection of the virus followed by isolation of the infected person at the earliest possible is the only measure to prevent this disease. Although there are number of methods available for detection of virus and to combat this disease in the present pandemic situation, but these available diagnostic methods have their own limitations. The speedy and exponential global spread of this disease strongly urges the fast and economic diagnostics tools. Additional to the available diagnostic methods, there is a sudden surge for development of various of methods and platforms to diagnose the COVID-19. The review summarized the advantage and disadvantage of various diagnostic approaches being used presently for COVID-19, newer detection methods in developmental stage and the feasibility of advanced platforms like newer nano-sensor based on-the-spot detection technologies.

Facile caffeine electrochemical detection via electrodeposited Ag nanoparticles with modifier polymers on carbon paste sensor at aqueous and micellar media

The analysis and detection of caffeine (Caf) is very useful due to its widespread usage in several daily consumed beverages, food products, and pharmacological preparations with various physiological effects. The preparation of a newly electrodeposited Ag nanoparticles – cellulose acetate phthalate (CAP) – chitosan (Chit) modified carbon paste (ACCMCP) sensor for sensitive determination of Caf in 0.01 mol L−1 H3PO4 solution (pH 1.0–5.0) both in aqueous and micellar media (0.5 mmol L−1 SDS) was achieved. The interaction of Caf was monitored using electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, and surface characterization was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray techniques. The linear detection range of Caf was between 4 and 500 μmol L−1 (r2 = 0.955) and the limit of detection obtained from the calibration plot was 0.252 μmol L−1. The sensor was applicable for detecting Caf in numerous real samples with recoveries from 98.03% to 101.60% without interference of any accompanying species, which ensures high method selectivity.

Novel spectrophotometric and factor-based multivariate calibration-prediction techniques for determination of two inhibitors of hepatitis C-virus and hepatocellular carcinoma in pure, human urine, and human plasma

Novel univariate and multivariate factor-based calibration-prediction techniques were validated for simultaneous ultraviolet spectrophotometric determination of ribavirin (RIV), daclatasvir (DAV), sofosbuvir (SOV), and sorafenib (SON) which are co-administered for treatment of hepatocellular carcinoma (HCC) that results from Hepatitis C-virus (HCV) infection in their commercial products and in biological fluids. Determination of these compounds is essential owing to their pharmacotherapeutic benefits. Due to spectral overlapping of RIV, DAV, SOV, and SON, univariate extended derivative ratio (EDR) method and multivariate partial least-squares (PLS) and principal component regression (PCR) methods were used for constructing the calibration curves. The extended derivative ratio (EDR) absorption maxima at 215 nm and minima at 310.5 nm was used for determination of RIV and DAV, respectively and absorption maxima at 240.3 nm and minima at 284.5 nm for determination of SOV and SON, respectively. The linearity was established over the range of 6-42 μg mL^-1, 4-16 μg mL^-1, 10-70 μg mL^-1, and 3-9 μg mL^-1 for RIV, DAV, SOV and SON with correlation coefficient (r2) of 0.9997, 0.9997, 0.9999 and 0.9997, respectively. This method was effectively applied to pure, pharmaceutical preparations and to spiked human urine and plasma. PLS and PCR models were established for the determination of the studied drugs in the range of 6-42, 4-16, 10-70 and 3-9 μg mL^-1 for RIV, DAV, SOV, and SON, respectively. Furthermore, updating the PLS model (PLS model update) were allowed for the determination of these drugs in spiked human urine, plasma and drug-dissolution test of their tablets. The obtained results were compared to official and reported method showing that there were no significant differences. The results of applying PLS and PCR models for evaluation of RIV, DAV, SOV, and SON in human urine samples as real samples were also encouraging. It is expected that the suitable features of the proposed method make it helpful for biological and clinical applications.

A clinical study for the evaluation of pharmacokinetic interaction between daclatasvir and fluoxetine

A simple and sensitive chromatographic method has been developed for the quantitative analysis of an antiviral agent, daclatasvir (DCV), that commonly prescribed for the treatment of hepatitis C viral (HCV) infection. The method was applied to detect DCV in human plasma and real blood samples collected from patients diagnosed with HCV and treated with DCV. The analysis strategy was based on recording the native fluorescence of DCV in plasma, after pre-column treatment to precipitate the plasma proteins using a readily applicable protocol. Chromatographic conductions, factors influencing the fluorescence and stability studies were also investigated. Furthermore, the method was validated according to the International Conference on Harmonization (ICH) guidelines and could be used to detect DCV in plasma over a linear range of 1.0-4000 ng/mL, with an acceptable sensitivity as the limit of detection (LOD) was 0.025 ng/mL. In addition, the study was extended to evaluate the pharmacokinetic interaction between DCV and a co-prescribed antidepressant drug, fluoxetine (FLX) in real blood samples, collected from volunteering patients who were diagnosed with HCV and treated with DCV alone or combined with FLX. The results showed a significant influence of FLX on the pharmacokinetic profile of DCV. The findings observed in this study could be used by clinical pharmacists to adjust the DCV dose, when combined with FLX, during the HCV treatment.

Stability-indicating micellar enhanced spectro-fluorometric determination of Daclatasvir in its tablet and spiked human plasma

A fast, simple and sensitive micellar enhanced spectrofluorimetric method is performed for the determination of Daclatasvir dihydrochloride (DAC) in its pharmaceutical dosage form and in spiked human plasma. The fluorescence intensity (FI) was measured at 367 nm after excitation at 300 nm. In aqueous solution, the FI of DAC was greatly enhanced by >110% in the presence of sodium dodecyl sulphate (SDS). The detection method was linear over the range of 12.93 to 161.60 ng/mL, with a limit of detection of 1.75 ng/mL. The proposed method was successfully applied to the determination of DAC in its pharmaceutical dosage form and the mean % recovery of DAC in spiked human plasma was 95.42 ± 2.52. The developed methodology was also extended to stress studies of DAC after exposure to different forced degradation conditions including acidic, alkaline, photolytic, thermal and oxidative environments.

Micellar spectrofluorimetric protocol for the innovative determination of HCV antiviral (daclatasvir) with enhanced sensitivity: Application to human plasma and stability study

Daclatasvir dihydrochloride (DAC) is a new, direct-acting antiviral drug with powerful inhibitory effect against all hepatitis C virus (HCV) genotypes. A sensitive, simple, fast and specific fluorometric method for estimation of DAC in the presence of sofosbuvir was developed and validated. The method is based on reinforcement the fluorescence intensity of DAC by 170% of its original value in an aqueous solution of hexadecyl trimethyl ammonium bromide (pH 5.5, Teorell and Stenhagen buffer). The fluorescence intensity measurements were accomplished at 387 nm with 328 nm for excitation wavelength. A linear relationship was achieved between the DAC concentration and the fluorescence intensity in a range of 50.0-2000.0 ng ml^-1 with 0.9998 and 0.9999 for the determination and correlation coefficients, respectively. The detection and quantitation limits were 13.4, 40.8 ng ml^-1, respectively. The excellent sensitivity and specificity of the proposed method allowed the efficient estimation of DAC in real human plasma with adequate recovery (81.78 ± 1.57), and the selective determination for DAC in its commercial dosage form without interference from tablet excipient. Moreover, the proposed method was expanded to examine the stability of DAC by determination the parent drug of DAC in the presence of its oxidative, alkaline, acidic, UV, daylight and sunlight degradations products in agreement with ICH guidelines. Furthermore, the kinetic study of acidic and oxidative degradations of DAC was inspected. In addition, the half-life times of the reaction (t_1/2) and the first-order reaction rate constants were estimated. Moreover, a suggestion for the degradation pathway was supposed.

A novel electrochemical analysis of the legal psychoactive drug caffeine using a zeolite/MWCNT modified carbon paste sensor

Caffeine (Caf) is a natural central nervous system stimulant categorized by the US Food and Drug Administration as a safe drug and its maximal amount in soft drinks has been approximately determined to be lower than 200 mg L⁻¹.

Mono and dual hetero-structured M@poly-1,2 diaminoanthraquinone (M = Pt, Pd and Pt–Pd) catalysts for the electrooxidation of small organic fuels in alkaline medium

Oxidation of some small organic fuels such as methanol (MeOH), ethanol (EtOH) and ethylene glycol (EG) was carried out in an alkaline medium using palladium (Pd)–platinum (Pt) nanoparticles/poly1,2-diaminoanthraquinone/glassy carbon (p1,2-DAAQ/GC) catalyst electrodes. Pd and Pt were incorporated into the p1,2-DAAQ/GC electrode using the cyclic voltammetry (CV) technique. The obtained Pd/p1,2-DAAQ/GC, Pt/p1,2-DAAQ/GC, Pt/Pd/p1,2-DAAQ/GC and Pd/Pt/p1,2-DAAQ/GC nanocatalyst electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and CV methods. Real active surface area (A_real) achieved by carbon monoxide (CO) adsorption using differential electrochemical mass spectroscopy (DEMS) technique. The electrochemical activity was evaluated and normalized to A_real per metal loading mass. The electrocatalytic oxidation of the small organic fuels at the prepared nanocatalyst electrodes was studied in 1.0 M NaOH solutions by CV and chronoamperometric (CA) techniques. Pt/Pd/p1,2-DAAQ/GC nanocatalyst electrode exhibited enhanced catalytic activity, better durability and higher tolerance to carbon monoxide generated in the oxidation reaction when compared with the other three studied nanocatalysts. The present investigation suggests that the studied nanocatalysts can be successfully applied in direct oxidation of small organic fuels, especially MeOH.

Oxidation reaction of some small organic fuels such as methanol, ethanol and ethylene glycol was carried out in alkaline medium at palladium (Pd)–platinum (Pt) nanoparticles/poly1,2-diaminoanthraquinone/glassy carbon catalyst electrodes.

Comparative study of six sequential spectrophotometric methods for quantification and separation of ribavirin, sofosbuvir and daclatasvir: An application on Laboratory prepared mixture, pharmaceutical preparations, spiked human urine, spiked human plasma, and dissolution test

In accordance with International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines, six novel, simple and precise sequential spectrophotometric methods were developed and validated for the simultaneous analysis of Ribavirin (RIB), Sofosbuvir (SOF), and Daclatasvir (DAC) in their mixture without prior separation steps. These drugs are described as co-administered for treatment of Hepatitis C virus (HCV). HCV is the cause of hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma) and lymphomas in humans. These techniques consisted of several sequential steps using zero, ratio and/or derivative spectra. DAC was first determined through direct spectrophotometry at 313.7 nm without any interference of the other two drugs while RIB and SOF can be determined after ratio subtraction through five methods; Ratio difference spectrophotometric method, successive derivative ratio method, constant center, isoabsorptive method at 238.8 nm, and mean centering of the ratio spectra (MCR) at 224 nm and 258 nm for RIB and SOF, respectively. The calibration curve is linear over the concentration ranges of (6-42), (10-70) and (4-16) μg/mL for RIB, SOF, and DAC, respectively. This method was successfully applied to commercial pharmaceutical preparation of the drugs, spiked human urine, and spiked human plasma. The above methods are very simple methods that were developed for the simultaneous determination of binary and ternary mixtures and so enhance signal-to-noise ratio. The method has been successfully applied to the simultaneous analysis of RIB, SOF, and DAC in laboratory prepared mixtures. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

Investigation of anti-Hepatitis C virus, sofosbuvir and daclatasvir, in pure form, human plasma and human urine using micellar monolithic HPLC-UV method and application to pharmacokinetic study

Simultaneous determination of sofosbuvir (SOF), and daclatasvir (DAC) in their dosage forms, human urine and human plasma using simple and rapid micellar high performance liquid chromatographic method coupled with UV detection (HPLC-UV) had been developed and validated. These drugs are described as co-administered for treatment of Hepatitis C virus (HCV). HCV is the cause of Hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma) and lymphomas in humans. Separation and quantitation were carried out on anonyx™ C₈ monolithic (100 × 4.6 mm (i.d.) analytical column maintained at 25 °C. The mobile phase consisted of 0.1 M sodium dodecyl sulfate (SDS) solution containing 20% (V/V) n-propanolol and 0.3% (V/V) triethylamine and pH was adjusted to 6.5 using 0.02 M phosphoric acid, respectively. The retention times of SOF and DAC were 4.8 min, and 6.5 min, respectively. Measurements were made at flow rate of 0.5 mL/min with injection volume of 20 μL and ultraviolet (UV) detection at 226 nm. Linearity of SOF and DAC was obtained over concentration ranges of 50-400, and 40-400 ng/mL, respectively in pure form, 60-300 and 50-300 ng/mL, respectively for human plasma and over 50-400, and 40-400 ng/mL, respectively for human urine with correlation coefficient >0.999. The proposed method demonstrated excellent intra- and inter-day precision and accuracy. The suggested method was applied for determination of the drugs in pure, dosage form, and in real human plasma, real human urine and drug-dissolution test of their tablets. The obtained results have been statistically compared to reported method to give a conclusion that there is no significant differences.

Development and validation of LC-MS/MS method for simultaneous determination of sofosbuvir and daclatasvir in human Plasma: Application to pharmacokinetic study

A simple and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) bioanalytical method was developed and fully validated for the first time for the simultaneous determination of newly discovered antiviral drugs, namely sofosbuvir (SOF) and daclatasvir (DAC) in human plasma. Tadalafil (TAD) was used as internal standard (IS). SOF, DAC and TAD (IS) were extracted from plasma using liquid-liquid extraction technique with methyl tert-butyl ether. The chromatographic separation was carried out using ZorbaxSB-C₁₈ column (4.6 × 50 mm,5 μm) and 5 mm ammonium formate buffer (pH 3.5)-acetonitrile (50:50, v/v) as mobile phase in an isocratic elution mode pumped at a flow rate 0.7 mL min^-1 . The quantitation was performed on API4500 triple quadrupole tandem mass spectrometer with positive electrospray ionization interface in multiple reaction monitoring mode. Validation was applied according to US Food and Drug Administration guidelines for bio-analytical methodswith respect to linearity, precision, accuracy, selectivity, carry-over, stability and dilution integrity. Linearity was obtained over concentration ranges of 0.3-3000 and 3-3000 ng mL^-1 for SOF and DAC, respectively, by applying a weighted least-squares linear regression method (1/x² ). The proposed method could be applied successfully in bioequivalence and/or clinical studies for therapeutic drug monitoring of patients undergoing dual combination therapy as the latter combination proved more efficacious and powerful tool for the complete treatment of hepatitis C genotype 3 within 16 weeks. The suggested method has been applied successfully to pharmacokinetic studies with excellent assay ruggedness and reproducibility.

Electrocatalytic oxidation of ethanol at Pd, Pt, Pd/Pt and Pt/Pd nano particles supported on poly 1,8-diaminonaphthalene film in alkaline medium

An ethanol oxidation reaction (EOR) in alkaline medium was carried out at palladium (Pd) or platinum (Pt) nanoparticles/poly 1,8-diaminonaphthalene (p1,8-DAN) composite catalyst electrodes. Pd and Pt were incorporated onto a p1,8-DAN/GC electrode by a cyclic voltammetry (CV) strategy. The obtained Pd/p1,8-DAN/GC, Pt/p1,8-DAN/GC, Pt/Pd/p1,8-DAN/GC and Pd/Pt/p1,8-DAN/GC modified electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV) techniques. Electrode surface areas (ESAs) of the obtained catalysts were calculated by carbon monoxide (CO) adsorption using differential electrochemical mass spectroscopy (DEMS). The electrocatalytic oxidation of ethanol (EtOH) at the catalyst electrodes was considered in 0.5 M NaOH solutions by CV and chronoamperometric techniques. The catalyst electrodes significantly enhanced the catalytic efficiency for EOR compared to a bare glassy carbon (GC) electrode. Bimetallic catalyst electrodes demonstrate improved catalytic activity, superior durability and higher tolerance to (CO) poison generated in the development of EOR compared with Pd/p1,8-DAN and Pt/p1,8-DAN catalysts, giving priority to Pt/Pd/p1,8-DAN/GC electrodes. Viability parameters, such as NaOH and EtOH concentrations, scan rate and upper potential limits, were examined and analyzed. This study suggests that the prepared catalysts have pronounced potential applications in direct EOR in fuel cells.

An ethanol oxidation reaction (EOR) in alkaline medium was carried out at palladium (Pd) or platinum (Pt) nanoparticles/poly 1,8-diaminonaphthalene (p1,8-DAN) composite catalyst electrodes.

The application of a bee glue-modified sensor in daclatasvir dual effect detection

A simple and novel carbon paste sensor containing chemically mixed propolis (bee glue) and graphene oxide (GO) was prepared, then electrochemical deposition of silver nanoparticles (AgNPs) was performed to fabricate a selective and sensible electrochemical sensor to detect Daclatasvir (DAC).