Simultaneous determination of acetaminophen, pramipexole and carbamazepine by ZSM-5 nanozeolite and TiO2 nanoparticles modified carbon paste electrode

Electrochemical Kinetics and Detection of Paracetamol by Stevensite-Modified Carbon Paste Electrode in Biological Fluids and Pharmaceutical Formulations

Paracetamol (PCT), or acetaminophen, is an important drug used worldwide for various clinical purposes. However, the excessive or indiscriminate use of PCT can provoke liver and kidney dysfunction; hence, it is essential to determine the amount of this target in biological samples. In this work, we develop a quick, simple, and sensitive voltammetric method using chemically modified electrodes to determine PCT in complex matrices, including human serum and commercial solid formulations. We modify the carbon paste electrode with stevensite monoclinic clay mineral (Stv-CPE), using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy to characterise and detect PCT. The kinetics study provides a better electrochemical characterisation of the electrode behaviour, finding the detection and quantitation limits of 0.2 μM and 0.5 μM under favourable conditions. Further, the best linear working concentration range is 0.6-100 μM for PCT, applying the proposed method to the quantitative determination of PCT content in reference tablet formulations and biological samples for validation.

Nickel-Cobalt Salen Organometallic Complexes Encapsulated in Mesoporous NaA Nanozeolite for Electrocatalytic Quantification of Ascorbic Acid and Paracetamol

Goal of current study was fabrication of novel voltammetric nanosensor for the synchronize quantification of ascorbic acid (AA) and paracetamol (PAR) by nickel-cobalt salen complexes encapsulated in the supercages of NaA nanozeolite modified carbon paste electrode (NiCoSalenA/CPE). For this purpose, NiCoSalenA nanocomposite was firstly prepared and characterized by various methods. Also, cyclic voltammetry (CV), choronoamperometry (CHA) and differential pulse voltammetry (DPV) were utilized to evaluate performance of the modified electrodes. The effects of pH and modifier amount were considered on the electrochemical oxidation of AA and PAR on the surface of NiCoSalenA/CPE. Results from this method indicated that pH of 3.0 in phosphate buffer solution (0.1 M) and 15 wt% of NiCoSalenA nanocomposite in the modified CPE results in the maximum current density. The oxidation signals of AA and PAR was amplified affectively at NiCoSalenA/CPE versus unmodified CPE. The limit of detection (LOD) and linear dynamic range (LDR) for the simultaneous measurement of them were founds to be 0.82 and 2.73-80.70 for AA and 0.51 µM, 1.71-32.50 and 32.50-137.60 µM for PAR, respectively. The catalytic rate constants (kcat) were attained to be 3.73 × 107 and 1.27 × 107 cm3 mol-1 s-1 for AA and PAR via CHA method, respectively. Also, the amounts of diffusion coefficient (D) were found to be 1.12 × 10-7 and 1.92 × 10-7 cm2 s-1 for AA and PAR, respectively. The average value of electron transfer rate constant between NiCoSalenA/CPE and PAR was obtained to be 0.016 s-1. The NiCoSalen-A/CPE displayed worthy stability, repeatability and extraordinary recovery for simultaneous measurements of AA and PAR. Application of offered sensor was confirmed by quantifying concentrations of AA and PAR in human serum solution as a real sample.

Comparison of signal enhancement strategies for carbamazepine detection in undiluted human saliva using an electrochemical sensor with stencil-printed carbon electrodes

Carbamazepine (CBZ), a drug prescribed to prevent seizures in people with epilepsy, has a narrow therapeutic range such that patients would greatly benefit from personalized drug dosage recommendations. Saliva is an excellent sample for personalized monitoring of CBZ levels because saliva CBZ concentration correlates with the free concentration of CBZ in blood, and can be collected non-invasively. CBZ level quantification using electrochemical detection has been demonstrated in a variety of electrode systems and samples, however, human saliva presents a particular challenge in terms of its complex composition that can result in signal interference via a high background current at the potentials of interest for CBZ detection. Previous demonstrations of electrochemical detection of CBZ in saliva have included rigorous pre-treatment of the sample using centrifugation and high levels of dilution, which is not compatible with lower-resource field settings for patient monitoring of CBZ levels. In this work, we systematically investigate several strategies to improve the detection of CBZ in a background of undiluted human saliva using polymeric laminate-based devices with stencil-printed carbon electrodes; (i) adding the anionic surfactant sodium dodecyl sulfate to the saliva, (ii) filtering saliva to remove larger molecular weight species, (iii) plasma pretreatment of the device electrodes, and (iv) incubation of the sample on the electrodes. These methods enabled the quantification of therapeutically-relevant concentrations of CBZ in a background of human saliva without the need for saliva preprocessing like dilution.

Direct and Sensitive Electrochemical Evaluation of Pramipexole Using Graphitic Carbon Nitride (gCN) Sensor

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 (L_D) 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.

Chemically modified carbon-based electrodes for the determination of paracetamol in drugs and biological samples

Paracetamol is a non-steroidal, anti-inflammatory drug widely used in pharmaceutical applications for its sturdy, antipyretic and analgesic action. However, an overdose of paracetamol can cause fulminant hepatic necrosis and other toxic effects. Thus, the development of advantageous analytical tools to detect and determine paracetamol is required. Due to simplicity, higher sensitivity and selectivity as well as costefficiency, electrochemical sensors were fully investigated in last decades. This review describes the advancements made in the development of electrochemical sensors for the paracetamol detection and quantification in pharmaceutical and biological samples. The progress made in electrochemical sensors for the selective detection of paracetamol in the last 10 years was examined, with a special focus on highly innovative features introduced by nanotechnology. As the literature is rather extensive, we tried to simplify this work by summarizing and grouping electrochemical sensors according to the by which manner their substrates were chemically modified and the analytical performances obtained.

A Comprehensive Review on Developed Pharmaceutical Analysis Methods by Iranian Analysts in 2018

This article summarizes the publishing activities including bioanalytical and pharmaceutical analyses researches carried out in Iran in 2018 in order to connect academic researchers to those in industry, medical care units and hospitals. A wide spectrum of analytical methods has been used to determine and/or evaluate drug levels in the biological samples, based on physical, chemical and biochemical principles. We have compiled a concise survey of the literature covering 125 reports and tabulated the relevant analytical parameters. Chromatographic and electrochemical methods were found to be the technique of choice for many workers and almost 83% studies were performed by using these methods. This is the first annual review of the literature searching in SCOPUS database for published bioanalytical and pharmaceutical analysis researches in Iran.

Developments and applications of nanomaterial-based carbon paste electrodes

This review summarizes the progress that has been made in the past ten years in the field of electrochemical sensing using nanomaterial-based carbon paste electrodes. Following an introduction into the field, a first large section covers sensors for biological species and pharmaceutical compounds (with subsections on sensors for antioxidants, catecholamines and amino acids). The next section covers sensors for environmental pollutants (with subsections on sensors for pesticides and heavy metal ions). Several tables are presented that give an overview on the wealth of methods (differential pulse voltammetry, square wave voltammetry, amperometry, etc.) and different nanomaterials available. A concluding section summarizes the status, addresses future challenges, and gives an outlook on potential trends.

Recent advances in electroanalytical methods for the therapeutic monitoring of antiepileptic drugs: A comprehensive review

Frequency of seizures is often managed by a wide group of antiepileptic drugs. Regarding the pharmacokinetic variability, narrow targeted range, and difficulty of detecting signs of toxicity based on laboratory responses, therapeutic monitoring of antiepileptic drugs can play a pivotal role in optimizing the drug dosage. Electrochemical sensors and biosensors can facilitate analysis of these drugs due to their unique advantages such as fast analysis, sensitivity, selectivity, and low cost. This review article, for the first time, describes the recent advances in electrochemical sensors and biosensors developed for the analysis of antiepileptic drugs. General electrochemical measuring techniques and types of applied electrode substrates were described first. To simplify the work, various chemical and biological modifiers applied to improve the sensitivity and selectivity of the sensors were classified and explained briefly. Finally, the future prospective on the development of electrochemical platforms in the quantification of antiepileptic drugs will be presented.

Preparation and characterization of novel MWCNTs/Fe-Co doped TNTs nanocomposite for potentiometric determination of sulpiride in real water samples

Novel multiwalled carbon nanotubes/ Fe-Co doped titanate nanotubes nanocomposite (MWCNTs/Fe-Co doped TNTs) facilitated the charge transfer and enhanced sensitivity and selectivity. Herein, three novel modified carbon paste sensors (CPSs) based on MWCNTs (sensor I), Fe-Co doped TNTs (sensor II) and MWCNTs/Fe-Co doped TNTs composite (sensor III) were fabricated for a simple, low cost and high accuracy electrochemical method for the potentiometric determination of sulpiride (SLP). The sensors exhibited excellent Nernstian slopes 57.1 ± 0.4, 56 ± 0.5 and 58.8 ± 0.2 mV decade⁻¹ with detection limits (DL) 7.6 × 10⁻⁷, 1.58 × 10⁻⁶ and 8.7 × 10⁻⁸ mol L⁻¹, quantification limits (QL) 2.5 × 10⁻⁶, 5.2 × 10⁻⁶ and 2.9 × 10⁻⁷ mol L⁻¹ for a long lifetime 20, 18, and 25 weeks for sensors (I), (II), and (III), respectively. The modified sensor (III) was applicable by measuring the concentration of spiked SLP in pure solutions, pharmaceutical products, human urine, and real water samples. The proposed method can be used as an important analytical tool in the quality control of the pharmaceutical industry.

Comparative Electroanalytical Studies of Graphite Flake and Multilayer Graphene Paste Electrodes

In this paper, the fabrication, surface characterisation and electrochemical properties of graphite flake (GFPE) and multilayer graphene (MLGPE) paste electrodes are described. The Raman investigations and scanning electron microscopy were used to analyze and compare structure of both carbon materials. The electroanalytical performance of both electrodes was examined and compared on the basis of the square-wave and cyclic voltammetric behavior of acetaminophen and model redox systems. Results of those studies revealed that GFPE has a larger electroactive surface area and better conductive properties, whilst MLGPE demonstrate better analytical characteristic in case of acetaminophen (AC) determination. AC determination was developed using square wave voltammetry (SWV) and square wave stripping voltammetry (SWSV). For both working electrodes, the process of accumulation enabled us to obtain an extended linear range and to lower the detection limit. In pharmaceutical formulations, AC was determined with good recovery.

TiO2 and N-TiO2 Sepiolite and Zeolite Composites for Photocatalytic Removal of Ofloxacin from Polluted Water

TiO₂ sepiolite and zeolite composites, as well the corresponding N-doped composites, synthesized through a sol–gel method, were tested for the photocatalytic degradation of a widespread fluoroquinolone antibiotic (ofloxacin) under environmental conditions. The catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) analyses. A complete drug degradation occurred in 10–15 min in the presence of both TiO₂ sepiolite and zeolite catalysts, and in 20–30 min with the N-doped ones. Sepiolite proved to be a better TiO₂ support compared to the most common zeolite both in terms of adsorption capacity and photocatalytic efficiency in pollutants degradation. The influence of nitrogen doping (red shift from 3.2 to 3.0 eV) was also investigated. Although it was blurred by a marked increase of the particle dimension and thus a decrease of the specific surface area of the doped catalysts, it allowed a faster drug removal than direct photolysis. The photochemical paths and photoproducts were investigated, too.

Synthesis of bifunctional cabbage flower-like Ho3+/NiO nanostructures as a modifier for simultaneous determination of methotrexate and carbamazepine

Cabbage flower-like Ho³⁺/NiO nanostructure (CFL-Ho³⁺/NiO NSs) with significant electrocatalytic oxidation has been published for the first time. First, structure and morphology of CFL-Ho³⁺/NiO-NSs have been described by XRD, SEM, and EDX methods. Then, CFL-Ho³⁺/NiO-NSs have been applied as a modifier for simultaneous electrochemical detection of methotrexate (MTX) and carbamazepine (CBZ). Functions of the modified electrode have been dealt with through electrochemical impedance spectroscopy (EIS). It has been demonstrated that the electrode response has been linear from 0.001-310.0 μM with a limit of detection of 5.2 nM and 4.5 nM (3 s/m) through DPV for MTX and CBZ. Diffusion coefficient (D) and heterogeneous rate constant (k_h) have been detected for MTX and CBZ oxidation at the surface of the modified electrode. Moreover, CFL-Ho³⁺/NiO-NS/GCE has been employed for determining MTX and CBZ in urine and drug specimens. Outputs showed the analyte acceptable recovery. Therefore, the electrode could be applied to analyze both analytes in drug prescription and clinical laboratories. Graphical abstract Electrochemical sensor based on bifunctional cabbage flower-like Ho³⁺/NiO nanostructures modified glassy carbon electrode for simultaneous detecting methotrexate and carbamazepine was fabricated.

Preparation and evaluation of a porous molecularly imprinted polymer for selective recognition of the antiepileptic drug carbamazepine

A novel and porous molecularly imprinted polymer (PMIP) was synthesized and used as a solid-phase extraction adsorbent for preconcentration of carbamazepine (CBZ) prior to its quantitation by high-performance liquid chromatography (HPLC) in various sample forms (e.g., drinking water, river water, hospital wastewater, and pharmaceuticals). PMIP-CBZ was applied to a polymerization process in which polystyrene spheres were coated with a silica layer. Removal of polystyrene spheres and formation of porous silica facilitated the recovery of CBZ (99.4%) during the extraction process. Site accessibility to the surface of PMIP-CBZ increased the density of high-recognition sites. PMIP-CBZ was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. The key variables influencing the extraction efficiency of PMIP (e.g., adsorbent loading, eluent type, eluent volume, reusability of the adsorbent, and cross-reactivity) were optimized. The optimized protocol was successfully employed to quantify CBZ with limit of detection and limit of quantification as 0.082 and 0.270 ng/mL, respectively (linear detection range: 0.5-250 ng/mL and a relative standard deviation:  < 5%). Use of the PMIP adsorbent resulted in a sensitive and stable method for efficiently quantitation of CBZ from various real sample matrices.

A novel low-dimensional heteroatom doped Nd2O3 nanostructure for enhanced electrochemical sensing of carbendazim

Reasonable design and synthesis of high-efficiency nanocatalysts are of great significance for studying the electrocatalytic analysis of fungicides.