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Background: Electrochemical methods in drug analysis have a lot of advantages, including simplicity, speed, low-cost instrumentation, informing about the drug mechanism, and nonaffection by excipients in dosage forms. Electrochemical techniques utilize the advantages of nanomaterials to increase sensitivity and, in some cases, selectivity. Among these nanomaterials, metal oxide nanoparticles are also preferred by researchers because of their unique properties such as biocompatibility, stability, non-toxicity, and catalytic characteristic. Objective: This review provided brief information about metal oxide nanoparticles used in electrochemical sensors and summarized applications for drug analysis with these sensors in tables showing the studies in the literature during the last decade. Results: In the last decade, metal oxides are frequently used in electrochemical drug analysis as electrode modifier individually and with other nanomaterials especially carbon-based ones. All these studies showed that metal oxide nanoparticles increase the active surface area of the electrode and the catalytic activity. Conclusion: When metal oxide nanoparticles and carbon-based nanomaterials are used together, they create a synergistic effect that further increases catalytic activity and thus lowers detection limits to be obtained in nM even pM levels.

Cefpirome, which is a fourth-generation cephalosporin, was analyzed for the first time at a glassy carbon electrode using differential pulse voltammetry in this novel method. Different experimental conditions were optimized, such as pH and electrolyte type, to achieve a high peak current. Under the optimum conditions, the oxidation of cefpirome exhibited diffusion-controlled process depending on pH. Cefpirome was electrochemically determined at the linear range between 2-200 µM, and the detection limit was found as 0.167 µM in pH 4.7 acetate buffer solution. Analysis results showed that the proposed electrochemical method could be used for the determination of cefpirome in human urine samples. A linear relationship has been obtained in the concentration range of 2-10 µM. At the same time, the detection limit was found as 0.101 µM for cefpirome in human urine. Moreover, to check the selectivity of the proposed method, the effect of some interference species, including ascorbic acid, uric acid, dopamine, glucose, 〖"Na" 〗^"+" , "K" ^"+" , 〖"Ca" 〗^"+2" , 〖"NO" 〗_"3" ^"-" , have also been investigated. As a result, a simple, sensitive, reproducible, no time-consuming, and more environmentally friendly method was developed when compared to the literature studies.

Background In the near future, sensitive, rapid and economical detection of food allergens will remain a hardship to the health promotion of the community. Biogenic Amines (BAs) are a type of food allergens, and due to the trace level and complexity of BAs, improvement of professional and cost-effective detection techniques has become particularly demanding. Since vegetables, canned and fresh fish, beverages, and fermented foods have high concentrations of BAs and are mainly consumed, the advancement of specific and finely tuned methods for quick diagnosis of BAs are exceedingly urgent. Scope and approach In this review, enzyme-based biosensors for BAs detection in foods with different transducers such as chemiluminescent, surface-enhanced raman scattering biosensors electrochemical, and fluorescence biosensors are presented. Nanozymes-based detection of BAs in foods are also discussed with recent applications. Moreover, the latest advances of BAs detection by enzyme-based biosensors and nanozyme-based methods are further tabulated. Key findings and conclusion Among modern diagnostic techniques, biosensors are economical, simple, and precise instruments for BAs detection. In the future, studying novel biosensors such as multifunctional nanocomposite biosensors will satisfy the demand for the enhancement of food safety and cost-effective nanozyme-based methods for BAs detection.

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.

Carbon-Based Composite Materials for Electrodes is a new open Special Issue of Materials, which has the goal of publishing original research and review articles focused on carbon nanotubes, graphene, activated carbon, graphite, pencil graphite, graphene oxide, graphene nanoplatelets, pyrolytic graphite, organic mass derived carbon, fullerenes, diamond, glassy carbon, carbon fibers, and other composites for electrode preparation and its applications [...]

A sandwich-type electrochemical aptasensor was designed for sensitive detection of leptin in biological samples, including human serum and human plasma. The developed aptasensor was produced by electrodeposition of gold nanoparticles on a screen-printed electrode modified with zinc oxide nanoparticles. The synergy effect of zinc oxide and gold nanoparticles improved the electrocatalytic activity of the aptasensor. The obtained high surface area allowed more aptamer molecules to be loaded on the electrode surface. Signal amplification significantly increases the detection sensitivity of a developed biosensor. Although the use of nanomaterials is the most preferred detection tool for this purpose, as an alternative, enzyme-catalyzed signal amplification is widely used in the construction of a biosensor due to its specificity and high catalytic efficiency. Therefore, both nanomaterial-supported and an alkaline phosphatase-based aptasensor design were developed, which can produce in situ electroactive product by enzymatic hydrolysis of the inactive substrate to achieve a higher signal-to-background ratio. Under optimal conditions, the developed aptasensor exhibited a wide linear concentration range from 0.01 pg mL

Abstract: Mepivacaine, an amide-type local anesthetic drug widely used in regional anesthesia, was studied by some aspects such as electrochemical behavior, mechanism illumination, and analytical applications by cyclic voltammetry (CV) and different pulse voltammetry (DPV) methods. In this study, a novel, fast, simple, portable, and the inexpensive electrochemical sensor was developed for the determination of mepivacaine. This study was carried out by mepivacaine anodic direction detection for the first time. The modified sensor was fabricated with silver nanoparticles (AgNP) and multiwalled carbon nanotubes paste electrode (MWCNTPE) by using the drop-dry method. Different experimental parameters, such as pulse amplitude, step potential, and scanning rate in the DPV application module, were optimized. Under optimal operation conditions, the limit of detection (LOD) as low as 31 μg L-1 was found over the dynamic range (0.1–8.0 mg L-1). In contrast to its high response towards mepivacaine, the DPV exhibits negligible responses on modified AgNP/MWCNTPE when exposed to interfering species such as dopamine, uric acid, glucose, ascorbic acid, and some heavy metals. Exceptionally, the proposed DPV method on modified AgNP/MWCNTPE was successfully applied to pharmaceutical dosage form and synthetic human serum with a low relative standard deviation (RSD) of 1.35% and 2.02%, respectively. background: In this study, a novel, fast, simple, portable, and inexpensive electrochemical sensor was developed for the determination of mepivacaine. objective: This study was carried out by mepivacaine anodic direction detection for the first time. The modified sensor was fabricated with silver nanoparticles (AgNP) and multiwalled carbon nanotubes paste electrode (MWCNTPE) by using drop-dry method. result: Under optimal operation conditions, the limit of detection (LOD) as low as 31 μg L-1 was found over the dynamic range (0.1–8.0 mg L-1).

Fixed dose combinations of ezetimibe and rosuvastatin are well known to provide significantly superior efficacy to rosuvastatin alone in lowering total cholesterol, and triglyceride levels. Therefore, in this recent work, we prepared fixed dose (10mg/10mg) ezetimibe and rosuvastatin tablet formulations, and a simple, selective and we established and validated rapid chromatographic method for the sensitive and simultaneous determination of rosuvastatin and ezetimibe. We performed the separation on Zorbax SB-C18 (100 mm x 4.6 mm, 3.5 µm particle size) column at 30 oC with a mobile phase that has a composition as water containing 0.1% H3PO4:methanol:acetonitrile (50:25:25 v/v/v) at 1.2 mL/min flow rate. We further performed validation studies according to ICH guidelines. Furthermore, we exposed rosuvastatin and ezetimibe to degradation conditions. We plotted peak area vs. concentration graphs for rosuvastatin and ezetimibe and used for defining the linearity of the detector response. In this suggested method, we observed linear relationships varying from 0.05 to 50 µg/mL for ezetimibe concentrations and from 0.05 to 25 µg/mL for rosuvastatin concentrations. We found the limit of detection values for rosuvastatin and ezetimibe as 0.006 and 0.008 µg/mL, respectively. Moreover, we further used the established method for to the analysis of ezetimibe and rosuvastatin from real spiked samples of rabbit serum.

Background: This review investigates the ophthalmic drugs that have been studied with voltammetry in the web of science database in the last 10 years. Introduction: Ophthalmic drugs are used in the diagnosis, evaluation and treatment of various ophthalmological diseases and conditions. A significant literature has emerged in recent years that investigates determination of these active compounds via electroanalytical methods, particularly voltammetry. Low cost, rapid determination, high availability, efficient sensitivity and simple application make voltammetry one of the most used methods for determining various kinds of drugs including ophthalmic ones. Methods: In this particular review, we searched the literature via the web of science database for ophthalmic drugs which are investigated with voltammetric techniques using the keywords of voltammetry, electrochemistry, determination and electroanalytical methods. Results: We found 33 types of pharmaceuticals in nearly 140 articles. We grouped them clinically into seven major groups as antibiotics, antivirals, non-steroidal anti-inflammatory drugs, anti-glaucomatous drugs, steroidal drugs, local anesthetics and miscellaneous. Voltammetric techniques, electrodes, optimum pHs, peak potentials, limit of detection values, limit of quantification values, linearity ranges, sample type and interference effects were compared. Conclusion: Ophthalmic drugs are widely used in the clinic and it is important to determine trace amounts of these species analytically. Voltammetry is a preferred method for its ease of use, high sensitivity, low cost, and high availability for the determination of ophthalmic drugs as well as many other medical drugs. The low limits of detection values indicate that voltammetry is quite sufficient for determining ophthalmic drugs in many media such as human serum, urine and ophthalmic eye drops.

The aim of this study is to develop a selective liquid chromatographic method for the simultaneous determination of tamsulosin HCl and dutasteride which are used for prostate treatment, in the context of an analytical column that is packed with superficially porous particles. Therefore, compositions of the mobile phase were determined for the best separation of these compounds. For this reason, experimental conditions such as varied pH values of buffer solution, temperature of the column, additives, flow rate of mobile phase and different buffer solutions were optimized. As the final condition, Kinetex C 18 analytical column (150 × 4.6; 5 µm) (Phenomenex, USA) and an acetonitrile/water 60: 40 (v/v), 0.1% o-phosphoric acid (pH adjusted to 7.0 using 5 M with NaOH) as a mobile phase are used for the best chromatographic separation. The separation was carried out at 45 °C column temperature with detection at 220 nm, and rilpivirine was chosen as an internal standard. As a result, the proposed method under optimum conditions is easy of application, rapid, precise, sensitive, accurate and fully validated. Furthermore, there is no need for time-consuming sample preparation technique, and because of this reason, it can be applied to quality control laboratories simply. Also, the optimized method can be successfully applied for the in vitro biological samples.

In this study, the interaction between the phosphodiesterase-3 enzyme inhibitor drug milrinone and biomolecules was investigated by electrochemical, fluorescence spectroscopy, and molecular docking studies for the first time. The interaction between milrinone and biomolecules was investigated according to the decrease in deoxyguanosine oxidation signals of milrinone and calf thymus double-stranded deoxyribonucleic acid (ct-dsDNA) by cyclic voltammetry and differential pulse voltammetry. In fluorescence spectroscopy studies, a competitive study was conducted on ct-dsDNA by adding a well-known fluorescent methylene blue and ct-dsDNA solution. The fluorescent results showed that milrinone had a higher affinity for ct-dsDNA binding compared to methylene blue. Interaction studies show that milrinone binds to ct-dsDNA via a groove-binding mode, and the binding constant values ​​were calculated as 4.27 × 106 M−1 and 6.03 × 104 M−1 at 25 °C, based on cyclic voltammetry and spectroscopic results, respectively. As a result of the interaction of human serum albumin and milrinone, the binding coefficient was calculated as 4.11 × 106 M−1 by cyclic voltammetry. In addition, experimental results were confirmed by obtaining information about the possible spatial structure of the aggregate formed through theoretical calculations based on energy minimization for milrinone- ct-dsDNA and milrinone-human serum albumin mixtures with molecular insertion.

Interactive association of an antifungal drug, climbazole (CBZ) with the carrier protein in bovine circulation, bovine serum albumin (BSA) was explored by fluorescence and absorption spectroscopy along with in silico techniques. The fluorescence and absorption spectral alterations of the protein upon addition of CBZ affirmed the complex foration between CBZ and BSA. The inverse temperature dependence behaviour of the K

This study is designed to investigate the interaction of phenylpiperidine derivative drug paroxetine, which is an effective serotonin reuptake inhibitor and biomolecules through electrochemical, fluorescence spectroscopy, and molecular docking methods. The interaction between paroxetine and biomolecules was investigated by differ-ential pulse voltammetry according to the decrease in deoxyguanosine anodic oxidation signal of double -stranded calf thymus DNA. Fluorescence spectroscopy studies were performed by titrating paroxetine against double-stranded calf thymus DNA solution at four different temperatures. The fluorescent results showed that paroxetine had a great affinity to bind with double-stranded calf thymus DNA. Interaction studies demonstrate that paroxetine binds to double-stranded calf thymus DNA via intercalation binding mode, and the binding constant values were calculated as 7.24 x 104 M-1 and 1.52 x 104 M-1 at 25 degrees C, based on voltammetric and spectroscopic results, respectively. Moreover, with the aim of elucidating the interaction mechanism between paroxetine and double-stranded calf thymus DNA, electrochemical and fluorescence spectroscopy studies along with molecular docking analysis were made.

© 2022 Elsevier B.V.This study examines the interaction between pyrimidine nucleoside analogue azacytidine, an anti-leukemic drug, and DNA by employing electrochemical, UV–vis spectroscopy, fluorescence spectroscopy and molecular docking techniques. In the electrochemical technique, azacytidine and dsDNA interaction was investigated in two different ways: (1) in solution and (2) with a biosensor using differential pulse voltammetry (DPV) at a glassy carbon electrode. The interaction between azacytidine and dsDNA at increasing interaction times was investigated in line with the changes in adenine and guanine oxidation signals. In addition, interaction studies of polyguanine-azacytidine and polyadenine-azacytidine were performed with DPV. The binding constant values were calculated as 2.420 × 104 M−1 and 3.266 × 104 M−1 at 25 °C using UV and fluorescence spectroscopy, respectively. In conclusion, based on electrochemical and spectroscopic methods as well as molecular docking studies, it was predicted that azacytidine can bind to dsDNA via groove binding.

Interaction of two broadly used herbicides, aclonifen (ACF) and bifenox (BIF) with the major transporter in human circulation, human serum albumin (HSA) were examined using fluorescence and absorption spectral measurements combined with in silico analyses. Assessment of the fluorescence and absorption spectral results affirmed the complexation between ACF/BIF and HSA. Increase in the K

Since the investigation of the properties of ionic liquids, there has been an increasing interest in these materials in the field of sensors area due to their unique properties. The electrochemical and radiolytic stability of ionic liquids are prerequisites for using ionic liquids. In addition, a large number of ionic liquids can be synthesized with the combination of different anions and cations. Therefore, they are preferred to fabricate the electrochemical, optical sensors, and biosensors or used in electrolyte solutions as they promise a facile and low-cost way to examine the analytes due to their properties such as increasing the conductivity, optical properties, and stability, lowering the detection limit, facilitating the electron transfer and increasing the effective surface area of the electrode and sensor platform. All of those properties are powered with the use of nanomaterials in the modification of the sensors. In this review, general information about the properties of ionic liquids were given. Moreover, the recent developments in electrochemical and optical sensor applications in the last five years were summarized. Finally, the utilization of ionic liquids and nanomaterials in the modification of the sensor platform and the advances of the proposed sensors for the analyses taking place in different molecules were discussed.

Combined therapy for HIV treatment shows superior efficacy in comparison to single therapy. Furthermore, the separation and determination of the combined dosage forms hold a significant place in the pharmaceutical industry. Not only reverse phase high-performance liquid chromatography (HPLC) but also hydrophilic interaction liquid chromatography (HILIC) can be used for these purposes. Contrary to conventional RP systems, HILIC may be an alternative for the analysis of polar substances. The aim of this study was the step-by-step development of a simple, rapid, and reliable method for the simultaneous determination of antiviral compounds from their marketed formulation (Trizivir). In order to achieve this goal, various mobile phase systems, buffer types, and concentrations were prepared to provide an appropriate separation. Different types of columns were tested to find the best resolution and high efficiency for the studied compounds. The proposed method provided a simple procedure for the simultaneous analysis of abacavir, lamivudine, and zidovudine in their pharmaceutical preparation within approximately 2 min using the conventional HPLC system. The developed method was fully validated according to the International Council for Harmonisation guidelines from the viewpoint of selectivity, sensitivity, precision, accuracy, linearity, limit of detection, and quantification.

Desloratadine is one of the most effective second-generation antihistamines and the electrochemical behavior of the active agent of desloratadine was investigated with a new nanosensor designed with the addition of zinc oxide and multiwalled carbon nanotube (ZnO : MWCNT) mixture on glassy carbon (GCE). By investigating and using cyclic, differential pulse and square wave voltammetry techniques with ZnO : MWCNT/GCE, it is planned to obtain information about quantification and mechanism of desloratadine. The efficiency of experimental parameters such as pH, scan rate, accumulation potential and time on the anodic response of desloratadine were studied. Differential pulse voltammetry was selected as assay method and under developed method and optimized conditions, the current showed linear dependence with concentration in the range between 2x10(-8) and 8x10(-6) M in pH 5.5 acetate buffer. The achieved limits of detection (LOD) and quantification (LOQ) are 0.769 nM and 2.56 nM respectively. Applicability of the methods was demonstrated by their implementation in pharmaceutical dosage forms of desloratadine and the accuracy, precision, selectivity, sensitivity, intra-day and day-to-day reproducibility of the methods were clearly explored. Finally, this sensor was successfully applied on real sample as a selective, simple, reproducible, repeatable an electrochemical sensor. Ankara University, Department of Scientific Research Project [17L0237001] The authors acknowledge the financial support of Ankara University, Department of Scientific Research Project (Project Number: 17L0237001). This work was produced from the PhD Dissertation of Kubra Ozturk (Ankara University, Health Sciences Institute). WOS:000483130300001 2-s2.0-85071050895

Oxymetazoline, a nasal decongestant drug was investigated by a sensitive, simple and reproducible electrochemical method using Titania (TiO2) nanoparticles and carboxyl group functionalized multi-walled carbon nanotubes fabricated on glassy carbon electrode using cyclic voltammetry and differential pulse voltammetry. The possible electro-oxidation mechanism of this drug was also studied in detail. The performance of designed method was determined by electrochemical impedance spectroscopy, cyclic voltammetry and anodic stripping differential pulse voltammetry. The obtained results revealed enhanced electrochemical behavior of oxymetazoline as compared to bare glassy carbon electrode. Under optimum conditions i.e. buffer pH; pH 7.0 phosphate buffer solution, accumulation potential; 0 V, and accumulation time; 180 s, the differential pulse voltammetric response of oxymetazoline was probed between the linear concentration range of 0.12 μM to 1.5 μM in aqueous medium containing pH 7.0 PBS and 20% methanol. The limit of detection of oxymetazoline was evaluated as 4.40 nM. Moreover, the developed sensing method was validated for its practical application in nasal spray with excellent recovery.

Background: Nanomaterials have a significant role in improving the performance of electrochemical sensing systems. Unique physical and chemical properties have extended the application of nanomaterials in the fields of engineering, materials and biomedical science. In the last few years, these materials with unique properties have been preferred in the design of experimental approaches for the analysis of metal ions, proteins, biomarkers and pharmaceutical compounds. This paper reports preparation, characterization of two different nanomaterials and their electrochemical application on doublestranded calf-thymus DNA signals. Methods: The multi-walled carbon nanotubes were functionalized with amine groups (MWCNTs-NH2) by employing the dielectric barrier discharge plasma treatment and then applied as MWCNTs- NH2/glassy carbon electrode. Moreover, the synthesized mesoporous silica MCM-41 was chemically amine functionalized and used as MCM-41-NH2/carbon paste electrode. For biosensor preparation, a thin layer of calf thymus double stranded deoxyribonucleic acid (ct-dsDNA) was immobilized over the modified electrodes. Results: The influence of dsDNA immobilized substrate was investigated based on the electrochemical signals. While dsDNA/MCM-41-NH2/carbon paste biosensor showed a selective effect for guanine signals, the dsDNA/MWCNTs-NH2/glassy carbon biosensor presented electrocatalytic effect for dsDNA signals. Both dsDNA modified electrodes were employed to explore the interaction between the dsDNA and the anticancer drug etoposide (ETP) in aqueous solution through voltammetric techniques. By increasing the interaction time with ETP, the adenine peak current was quenched in the presence of MWCNTs-NH2 based glassy carbon electrode. Whereas, in the presence of MCM-41-NH2 based CP electrode, selective interaction with guanine occurred and oxidation peak intensity was diminished. Conclusion: The selective effect of MCM-41-NH2 can be used when the studied substances give a signal with the same potential of adenine.

Lab-In-Syringe direct immersion single drop microextraction is proposed as an automated sample pretreatment methodology and coupled online to HPLC with fluorescence detection for the determination of fluoroquinolones in environmental waters. For the first time, a drop of a natural deep eutectic solvent (NADES), synthesized from hexanoic acid and thymol, has been used as an extractant in automated single-drop microextraction. The extraction procedure was carried out within the 5 mL void of an automatic syringe pump. A 9-position head valve served the aspiration of all required solutions, air, waste disposal, and hyphenation with the HPLC instrument. Sample mixing during extraction was done by a magnetic stirring bar placed inside the syringe. Only 60 μL of NADES were required omitting toxic classical solvents and improving the greenness of the proposed methodology. By direct injection, linear working ranges between 0.1 and 5 μg L