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Recent developments in nanoscale materials have found extensive use in various fields, especially in the biomedical industry. Several substantial obstacles must be overcome, particularly those related to nanostructured materials in biomedicine, before they can be used in therapeutic applications. Significant concerns in biomedicine include biological processes, adaptability, toxic effects, and nano-biointerfacial properties. Biomedical researchers have difficulty choosing suitable materials for drug carriers, cancer treatment, and antiviral uses. Carbon nanomaterials are among the various nanoparticle forms that are continually receiving interest for biomedical applications. They are suitable materials owing to their distinctive physical and chemical properties, such as electrical, high-temperature, mechanical, and optical diversification. An individualized, controlled, dependable, low-carcinogenic, target-specific drug delivery system can diagnose and treat infections in biomedical applications. The variety of carbon materials at the nanoscale is remarkable. Allotropes and other forms of the same element, carbon, are represented in nanoscale dimensions. These show promise for a wide range of applications. Carbon nanostructured materials with exceptional mechanical, electrical, and thermal properties include graphene and carbon nanotubes. They can potentially revolutionize industries, including electronics, energy, and medicine. Ongoing investigation and expansion efforts continue to unlock possibilities for these materials, making them a key player in shaping the future of advanced technology. Carbon nanostructured materials explore the potential positive effects of reducing the greenhouse effect. The current state of nanostructured materials in the biomedical sector is covered in this review, along with their synthesis techniques and potential uses.
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Nanopartículas , Nanoestruturas , Nanotubos de Carbono , Nanotubos de Carbono/química , Nanoestruturas/uso terapêutico , Nanoestruturas/química , Sistemas de Liberação de Medicamentos/métodos , Portadores de FármacosRESUMO
The abstract highlights the development of an electroanalytical sensor for the detection of 2-phenylphenol (2-PPL) as a contaminant. The novelty of the experiment lies in the utilization of a 1-D nanostructured WO3/CuO nanocomposite integrated with a carbon paste electrode (CPE). The hydrothermal method was used to synthesize the WO3 NPs, which were then characterized using Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) techniques. Tungsten oxides (WO3) have been the subject of extensive study because of their many desirable characteristics, including their ease of preparation, tunable stoichiometry, crystal structure, particle morphology, 2.6 eV bandgap, excellent photocatalytic oxidation capacity, non-toxic nature, and widespread availability. The narrow band gap in CuO makes it an ideal sensing material. Copper oxide has applications in many different industries because it is a semiconductor metal with a narrow band gap in the spectrum of 1.2-1.9 eV and unique optical, electrical, and magnetic properties. Techniques like cyclic voltammetry (CV), and square wave voltammetry (SWV) were used. Real sample analysis was carried out in real-world samples like different types of soil, vegetables, and water. The electroanalytical sensor showed outstanding catalytic behavior by enhancing the peak current of the 2-phenylphenol with the potential shift to the less positive side compared to the unmodified carbon paste electrode in the presence of pH 7.0 phosphate buffer solution (PB). Throughout the experimental study, double distilled was used. Various electro-kinetic parameters like pH, accumulation time study, scan rate, concentration variation, standard heterogeneous rate constant, and participation of electrons, accumulation time, and transfer coefficient have been studied at WO3/CuO/CPE. The limit of detection was quantified together with the limit of quantification. Possible electrochemical oxidation mechanism of the toxic molecule was depicted. Overall, this research contributes to the field of electroanalytical sensing and offers potential applications in environmental monitoring.
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To curtail pathogens or tumors, antimicrobial or antineoplastic drugs have been developed. These drugs target microbial/cancer growth and survival, thereby improving the host's health. In attempts to evade the detrimental effects of such drugs, these cells have evolved several mechanisms over time. Some variants of the cells have developed resistances against multiple drugs or antimicrobial agents. Such microorganisms or cancer cells are said to exhibit multidrug resistance (MDR). The drug resistance status of a cell can be determined by analyzing several genotypic and phenotypic changes, which are brought about by significant physiological and biochemical alterations. Owing to their resilient nature, treatment and management of MDR cases in clinics is arduous and requires a meticulous approach. Currently, techniques such as plating and culturing, biopsy, gene sequencing, and magnetic resonance imaging are prevalent in clinical practices for determining drug resistance status. However, the major drawbacks of using these methods lie in their time-consuming nature and the problem of translating them into point-of-care or mass-detection tools. To overcome the shortcomings of conventional techniques, biosensors with a low detection limit have been engineered to provide quick and reliable results conveniently. These devices are highly versatile in terms of analyte range and quantities that can be detected to report drug resistance in a given sample. A brief introduction to MDR, along with a detailed insight into recent biosensor design trends and use for identifying multidrug-resistant microorganisms and tumors, is presented in this review.
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Anti-Infecciosos , Antineoplásicos , Neoplasias , Humanos , Resistência a Múltiplos Medicamentos , Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêuticoRESUMO
Chlorinated organic compounds are useful chemicals or intermediates that are used extensively in both industry and agriculture. The 4-chlorophenol (4CP) in low concentration poses a serious environmental problem and causes many health issues, including cancer and liver disease. In this work, we demonstrated the detection of 4CP at carbon paste electrodes modified using tungsten oxide (WO3) nanorods and reduced graphene oxide (rGO) nanoparticles. The significance of pH on the voltammetric response of 4CP was investigated, and it was discovered that an alkaline pH is an optimal condition for detecting substituted phenols. Moreover, parameters like heterogeneous rate constant, accumulation time, temperature effect, Gibb's free energy, scan rate, enthalpy, activation energy, and entropy were studied. The excellent catalytic and bulk properties of tungsten oxide nanostructures make it an effective modifier in electrochemical sensors. The employment of nanostructured WO3 for the assay of 4CP offers excellent sensitivity, selectivity, and applicability. The WO3 nanostructures are obtained hydrothermally and characterized in detail to understand the crystalline, quantitative and chemical properties. The electrochemical behavior of 4CP was studied utilizing voltammetry techniques. The CV technique was used to optimize and affect many factors in the electrochemical behavior of 4CP. The scan rate investigation helps to examine the physicochemical characteristics of the electrode process, and the electrooxidation of 4CP included 2 electrons and 2 protons. With 4CP, the modified electrode displayed a broad range of linearity. The limit of detection was determined to be 0.102 nM, while the limit of quantification was 0.3433 nM. The concentration of 4CP ranged between 0.1 × 10-7 M and 3.5 × 10-7 M. The fabricated electrode was also used to detect 4CP in soil and water samples. Good recoveries were obtained from the soil and water samples. The proposed electrode was used for analytical applications, including 4CP detection with high selectivity, low detection limit, sensitivity, and rapid response.
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Grafite , Nanocompostos , Grafite/química , Nanocompostos/química , Eletrodos , Solo , Água , Técnicas Eletroquímicas/métodosRESUMO
Lab-on-a-chip (LOC) biosensors have recently piqued the interest of the research community as a result of its potential utility in personal healthcare and disease diagnostics. LOCs devices have been consistently developed over the last decades as merging microfluidics onto a single chip for performing many lab studies at the same time, such as biochemical and biomolecular detection. Molding, microcontact printing, micromachining, and other techniques were used in the preliminary advancement of miniature sensing platforms known as micro total analysis systems (µTAS). These time-consuming and multi-step processes were utilized to create structures on a micrometer size. As time passes, new approaches and modifications for replacing rigid substrates with flexible substrates were developed. Over the years, paper and plastic substrates have shown unique properties such as durability, flexibility, mobility, cost-effective, and simple manufacturing procedure owing to their compatibility with a wide range of printing equipment. This review discusses the different types of fabrication methods and techniques such as photolithography, soft lithography, screen printing, inkjet printing, laser micromachining, nanoimprinting for designing LOC sensing devices extensively. The types of transduction systems which includes electrochemical, optical and mechanical that play an important role in sensing devices have also been extensively described in this manuscript. Additionally, detection of numerous analytes categorized into small molecules, macromolecules and cell bodies have been comprehensively reviewed in this manuscript with illustrations and tabulated form.
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Dispositivos Lab-On-A-Chip , Microfluídica , Desenho de Equipamento , Impressão Tridimensional , PlásticosRESUMO
In recent years, an increasing amount of attention has been paid to utilizing dedicated waste biomass as a sustainable, cheap, and abundant fuel and material source. There is a tremendous opportunity for maximizing energy production by applying different reliable waste biomass as a renewable, affordable, and excellent resource. As a result of renewable hydrocarbons such as biomass, bioenergy is produced, green chemicals are manufactured, and carbon materials are made. Furthermore, biomass can be utilized as a source of advanced carbon materials. Carbon materials derived from biomass can also be used to support catalysts in fuel cells with polymer electrolyte membranes. For the fabrication of electrochemical sensors, porous carbonaceous materials generated from biomass are highly advised owing to their specific qualities, including regenerative nature, affordability, distinctive structure, and sustainability. The surface morphology of the sensor, especially its pore volume, surface area, and pore size affects both its electrochemical and catalytic activity. Metal nanoparticle activation, doping, and dispersion are just a few of the methods that may be used to improve the performance of sensors. To detect a variety of target analytes, such as biomolecules, metal ions, contaminants, food additives, and flavonoids, some of the key or seminal advances in the field of biomass-derived carbonaceous compounds are discussed. The materials and composites made of biomass-derived carbon will be in-depth examined, evaluated, and compared in this review. The associated technological difficulties are also discussed, and future research areas are suggested for use in practical applications. Nano carbon materials have several integrated advantages, including good electrical conductivity, structural and chemical flexibility, reduced chemical functionalization, and bulk production potential, making them viable candidates for various electrochemical processes. In the coming years, bio-carbon production from waste biomass is expected to gain rapid scientific and industrial interest because it will be used in electrochemical devices and rechargeable batteries. We emphasize the variety of waste biomass precursors that are accessible, as well as the recent developments in the manufacture of bio-carbon. Carbonaceous nanoparticles generated from biomass have shown potential for use in fuel cells, bioimaging, medicinal delivery, carbon fixation, catalysis, and gas sensors. Interestingly, this article has covered these nanomaterials' new and innovative energy conversion and storage services. Finally, the remaining difficulties, perspective views, and potential research trajectories in the area are described.
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Nanopartículas Metálicas , Nanoestruturas , Biomassa , Nanoestruturas/química , Catálise , PorosidadeRESUMO
Pramipexole (PMXL) belongs to the benzothiazole class of aromatic compounds and is used in treating Parkinson's disease; however, overdosage leads to some abnormal effects that could trigger severe side effects. Therefore, it demands a sensitive analytical tool for trace level detection. In this work, we successfully developed an electrochemical sensor for the trace level detection of PMXL, using the voltammetric method. For the analysis, graphitic carbon nitride (gCN) was opted and synthesized by using a high-temperature thermal condensation method. The synthesized nanoparticles were employed for surface characterization, using transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) techniques. The electrochemical characterization of the material was evaluated by using the electrochemical impedance spectroscopy (EIS) technique to evaluate the solution-electrode interface property. The cyclic voltammetry (CV) behavior of PMXL displayed an anodic peak in the forward scan, indicating that PMXL underwent electrooxidation, and an enhanced detection peak with lower detection potential was achieved for gCN-modified carbon paste electrode (gCN·CPE). The influence of different parameters on the electrochemical behavior was analyzed, revealing the diffusion governing the electrode process with an equal number of hydronium ions and electron involvement. For the fabricated gCN·CPE, good linearity range was noticed from 0.05 to 500 µM, and a lower detection limit (LD) of 0.012 µM was achieved for the selected concentration range (0.5 to 30 µM). Selectivity of the electrode in PMXL detection was investigated by conducting an interference study, while the tablet sample analysis demonstrates the sensitive and real-time application of the electrode. The good recovery values for the analysis illustrate the efficiency of the electrode for PMXL analysis.
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Técnicas Eletroquímicas , Grafite , Carbono/química , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Limite de Detecção , Compostos de Nitrogênio , PramipexolRESUMO
The electrochemical analysis of theophylline (THP) was investigated by fabricating a carbon paste electrode (CPE) modified with graphene oxide (GO) along with copper oxide (CuO) nanoparticles (CuO-GO/CPE). The impact of electro-kinetic parameters such as the heterogeneous rate constant, the scan rate, the accumulation time, the pH, the transfer coefficient, and the number of electrons and protons transferred into the electro-oxidation mechanism of THP has been studied utilizing electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The differential pulse voltammetry technique was employed to investigate THP in pharmaceutical and biological samples, confirming the limit of detection (LOD) and quantification (LOQ) of the THP. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to characterize the CuO nanoparticles. The CuO-GO/CPE was more sensitive in THP detection because its electrocatalytic characteristics displayed an enhanced peak current in the 0.2 M supporting electrolyte of pH 6.0, proving the excellent sensing functioning of the modified electrode.
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The leading cause of gynecological cancer-related morbidity and mortality is ovarian cancer (OC), which is dubbed a silent killer. Currently, OC is a target of intense biomarker research, because it is often not discovered until the disease is advanced. The goal of OC research is to develop effective tests using biomarkers that can detect the disease at the earliest stages, which would eventually decrease the mortality, thereby preventing recurrence. Therefore, there is a pressing need to revisit the existing biomarkers to recognize the potential biomarkers that can lead to efficient predictors for the OC diagnosis. This Perspective covers an update on the currently available biomarkers used in the triaging of OC to gain certain insights into the potential role of these biomarkers and their estimation that are crucial to the understanding of neoplasm progression, diagnostics, and therapy.
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Antígeno Ca-125 , Neoplasias Ovarianas , Algoritmos , Biomarcadores Tumorais , Carcinoma Epitelial do Ovário , Detecção Precoce de Câncer , Feminino , Humanos , Neoplasias Ovarianas/diagnóstico , Proteínas , Proteína 2 do Domínio Central WAP de Quatro DissulfetosRESUMO
Incorporating new pollutants and environmental pollution has become a formidable issue as new pollutants are introduced into it and have become a significant concern in recent years. Detection of such pollutants needs a susceptible, selective, and cost-effective sensor that can sense their presence and quantify them at a trace level. In the present study, we have designed a 2D graphene oxide (GO)-based glassy carbon electrode (GCE) electrochemical sensor (GO/GCE) and utilized it as a sensing material for the detection and determination of CRZ. The voltammetric behavior of CRZ was studied using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. The SWV was applied to quantify and analyze CRZ in actual samples. A better response of CRZ was noticed at GO/GCE when phosphate buffer solution of pH 4.2 was used as a supporting electrolyte for to experiment. The SWV technique achieved trace-level detection of CRZ. A linearity plot was obtained for the concentration range of 1.0 × 10-7 M to 2.5 × 10-4 M with a limit of detection of 1.38 × 10-8 M. The selectivity of the modified sensor was verified by the interference study of metal ions and other pesticides with CRZ. The agricultural and environmental significance of the developed method was successfully tested by estimating CRZ in water and soil samples.
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Poluentes Ambientais , Fungicidas Industriais , Grafite , Benzimidazóis , Carbamatos , Carbono , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de DetecçãoRESUMO
The use of the herbicide aminotriazole (3-ATA) in agriculture poses rising concerns about global water-borne contamination. Due to its toxicity which is known to cause cancer and thyroid dysfunction, 3-ATA is considered an important analytical target. Environmental protection agencies worldwide have introduced several directives that set concentration limits for chemicals to combat water pollution. Hence, to evaluate the presence of 3-ATA in water and limit their impact on ecosystems and human health, the development of an efficient real-time monitoring device is the key. The as-synthesized copper oxide decorated multiwall carbon nanotubes at 400 °C (CuO-MWCNT@400) showed remarkable efficiency as modifiers. Under optimal conditions, we explored the direct oxidation of 3-ATA at CuO-MWCNT@400 modified carbon paste electrode (MCPE). With its distinguishing synergistic features like high levels of porosity, stability, and surface area, this structure favoured greater detection, selectivity, and sensitivity. The amperometric i-t curve technique was adopted for the first time for 3-ATA quantification. This technique rendered a good detection sensitivity of 1.65 × 10-8 mol L-1 and anti-interference characteristics for several interferent species, including fungicides, fertilizers, herbicides, inorganic ions, and carbohydrates. Finally, the proof-of-concept was yielded by selective and sensitive detection of 3-ATA from two different samples of spiked water. We believe this work will enhance awareness and garner appreciation of the electrochemical sensor's analytical performance in protecting our environment and water resources.
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Herbicidas , Nanotubos de Carbono , Amitrol (Herbicida) , Ecossistema , Humanos , Nanotubos de Carbono/química , ÁguaRESUMO
Diabetes mellitus is a physiological and metabolic disorder affecting millions of people worldwide, associated with global morbidity, mortality, and financial expenses. Long-term complications can be avoided by frequent, continuous self-monitoring of blood glucose. Therefore, this review summarizes the current state-of-art glycemic control regimes involving measurement approaches and basic concepts. Following an introduction to the significance of continuous glucose sensing, we have tracked the evolution of glucose monitoring devices from minimally invasive to non-invasive methods to present an overview of the spectrum of continuous glucose monitoring (CGM) technologies. The conveniences, accuracy, and cost-effectiveness of the real-time CGM systems (rt-CGMs) are the factors considered for discussion. Transdermal biosensing and drug delivery routes have recently emerged as an innovative approach to substitute hypodermal needles. This work reviews skin-patchable glucose monitoring sensors for the first time, providing specifics of all the major findings in the past 6 years. Skin patch sensors and their progressive form, i.e., microneedle (MN) array sensory and delivery systems, are elaborated, covering self-powered, enzymatic, and non-enzymatic devices. The critical aspects reviewed are material design and assembly techniques focusing on flexibility, sensitivity, selectivity, biocompatibility, and user-end comfort. The review highlights the advantages of patchable MNs' multi-sensor technology designed to maintain precise blood glucose levels and administer diabetes drugs or insulin through a "sense and act" feedback loop. Subsequently, the limitations and potential challenges encountered from the MN array as rt-CGMs are listed. Furthermore, the current statuses of working prototype glucose-responsive "closed-loop" insulin delivery systems are discussed. Finally, the expected future developments and outlooks in clinical applications are discussed.
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Automonitorização da Glicemia , Diabetes Mellitus , Glicemia , Diabetes Mellitus/tratamento farmacológico , Humanos , Insulina , Sistemas de Infusão de InsulinaRESUMO
The electrochemical performance of linuron (LNR) was studied by fabricating the carbon paste electrode (CPE) using multiwalled carbon nanotubes (MWCNTs) along with zinc oxide (ZnO) nanoparticles (MWCNTs/ZnO/CPE). The influence of electro-kinetic specifications involving steady heterogeneous rate, pH, sweep rate, temperature effect, transfer coefficient, accumulation time, activation energy, as well as the total number of protons and electrons participating in electro-oxidation of LNR has been established using voltammetric techniques like cyclic voltammetry (CV) and square wave voltammetry (SWV). These techniques were applied to investigate LNR in real samples such as soil including water samples. Over the 0.02 µM-0.34 µM ranges, a linear relationship was confirmed along with the limit of detection and quantification (LOD and LOQ) of the LNR. The synthesized ZnO nanoparticles were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) analysis. The MWCNTs/ZnO/CPE sensor was considered sensitive for LNR detection because the sensor exhibited enhanced catalytic qualities with peak current in the involvement of 0.2 M phosphate buffer solution (PBS) of pH 6.0, attributed to the ultimate sensing performance of the sensor.
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Herbicidas , Nanotubos de Carbono , Óxido de Zinco , Técnicas Eletroquímicas , EletrodosRESUMO
Novel sensors based on carbon paste assorted with amberlite XAD-4 resin and silver-doped titanium dioxide/amberlite XAD-4 resin (Ag-TiO2/XAD) were designed and employed for sensitive detection of flufenamic acid (FFA). The main objective of this study is to develop novel electrochemical sensors for more sensitive and selective detection of FFA and to propose its oxidation mechanism. In this perspective, we have developed modified electrodes using amberlite XAD-4 matrix and Ag-TiO2/XAD-4 mixture. These sensors when used in conjunction with different voltammetric techniques to observe enhanced outcome on FFA electrode reaction in PBS of pH 7.0. Our data confirmed exceptional stability, sensitivity, and quick responses for FFA. The effect of modifier, analyte concentration, pH of buffer solution, pre-concentration time, and sweep rates on electrochemical behavior of FFA was investigated. The current intensities were linearly proportional to the concentration of FFA. From the calibration plot of different concentrations of FFA, the detection limit of 3.6 nM at XAD-CPE and 1.2 nM, respectively at AgTiO2/XAD-CPE were obtained. The estimation of FFA in biological as well as clinical samples was achieved using the chemically modified electrodes.
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Carbono/química , Técnicas Eletroquímicas , Ácido Flufenâmico/química , Poliestirenos/química , Polivinil/química , Prata/química , Titânio/química , Eletrodos , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Recent advances to utilize two or more nanoparticles for developing novel sensors with superior sensitivity have spurred advanced detection limits even at low concentrations. In this research, a blend of rutheniumdoped TiO2 (Ru-TiO2) nanoparticles and multiwalled carbon nanotubes (MWCNTs) loaded into carbon paste matrix to fabricate a novel Ru-TiO2/MWCNTs-CPE sensor was used for the detection and quantification of flufenamic acid (FFA) and mefenamic acid (MFA) drugs. The surface morphology of Ru-TiO2 was assessed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Sensitivity and selectivity of the electrode was improved at the Ru-TiO2/MWCNTs modified CPE compared to nascent CPE due to the amazing surface distinctive characteristics of the modifier at pH 5.0. The effect of concentration of the modifier, pH, pre-concentration time, sweep rate and concentration on signal enhancement of FFA and MFA was studied. The square wave voltammetry (SWV) currents are linearly related in the concentration range of 0.01⯵M-0.9⯵M with the detection limit values of 0.68â¯nM for FFA and 0.45â¯nM for MFA, respectively. The developed electrode assembly was used for the quantification of both the drug analytes in human urine samples.
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Eletroquímica/instrumentação , Ácido Flufenâmico/análise , Ácido Mefenâmico/análise , Nanopartículas/química , Nanotubos de Carbono/química , Rutênio/química , Titânio/química , Ácido Flufenâmico/química , Ácido Flufenâmico/urina , Humanos , Ácido Mefenâmico/química , Ácido Mefenâmico/urina , Fatores de TempoRESUMO
Electrochemical oxidation of acyclovir at fullerene-C(60)-modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry. In pH 7.4 phosphate buffer, acyclovir showed an irreversible oxidation peak at about 0.96V. The cyclic voltammetric results showed that fullerene-C(60)-modified glassy carbon electrode can remarkably enhance electrocatalytic activity towards the oxidation of acyclovir. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the acyclovir determination by differential pulse voltammetry. Effects of anodic peak potential (E(p)/V), anodic peak current (I(p)/µA) and heterogeneous rate constant (k(0)) have been discussed. Under optimized conditions, the concentration range and detection limit were 9.0×10(-8) to 6.0×10(-6)M and 1.48×10(-8)M, respectively. The proposed method was applied to acyclovir determination in pharmaceutical samples and human biological fluids such as urine and blood plasma as a real sample. This method can also be employed in quality control and routine determination of drugs in pharmaceutical formulations.
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Aciclovir/análise , Aciclovir/química , Carbono/química , Eletroquímica/métodos , Fulerenos/química , Vidro/química , Aciclovir/sangue , Aciclovir/urina , Antivirais/análise , Antivirais/sangue , Antivirais/química , Antivirais/urina , Calibragem , Eletroquímica/instrumentação , Eletrodos , Humanos , Oxirredução , Comprimidos , Fatores de TempoRESUMO
The voltammetric behavior of theophylline was investigated using cyclic and differential-pulse voltammetric techniques. The cyclic voltammetric results indicate that multi-wall carbon nanotube paste electrode can remarkably enhance electrocatalytic activity toward the oxidation of theophylline in pH 3.0 phosphate buffer solution than the carbon paste electrode. The oxidation of theophylline was observed to be a two-electron process, irreversible with diffusion character. Effects of anodic peak potential (E(p)), anodic peak current (I(p)) and heterogeneous rate constant (k(o)) have been discussed. Under optimal conditions, the anodic peak current was proportional to theophylline concentration in the range of 2.0×10(-6) to 1.5×10(-4)M with a detection limit of 1.97×10(-8)M using differential pulse voltammetry. The proposed method was employed to determine theophylline in pharmaceutical formulations and urine as a real sample.
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Eletrodos , Nanotubos de Carbono/química , Teofilina/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , NanotecnologiaRESUMO
The electrochemical oxidation of a hemorheologic drug, pentoxifylline was investigated at a multi-walled carbon nanotubes-paraffin oil paste electrode using cyclic and differential pulse voltammetry. The oxidation process was irreversible over the pH range studied and exhibited an adsorption-controlled behavior. All experimental parameters have been optimized. Under the optimum conditions, the oxidation peak current was linearly proportional to the concentration of pentoxifylline in the range of 3.0 × 10(-5) to 2.0 × 10(-4)M with a detection limit of 1.69 × 10(-7)M by differential pulse voltammetry with 180s accumulation. The proposed method was successfully applied to pentoxifylline determination in pharmaceutical and urine samples. Satisfactory recoveries of the analyte from the real samples and a good agreement between the concentration ranges studied and the real ranges encountered in the urine samples, when treated with the drug make the developed method applicable in clinical analysis. This method can also be employed in quality control and routine determination of drugs in pharmaceutical formulations.