Chiral voltammetric sensor for warfarin enantiomers based on carbon black paste electrode modified by 3,4,9,10-perylenetetracarboxylic acid

Advancements in electrochemical sensor technology for warfarin detection: a comprehensive review

Warfarin (WA), the most prescribed oral anticoagulant in patients with atrial fibrillation, is widely utilized for the treatment of various diseases, such as vascular disorders, venous thrombosis, and atrial fibrillation. However, its abnormal concentration is linked to a variety of disorders and diseases, namely bleeding while brushing teeth, skin tissue issues, hair loss, and chest pain. Therefore, WA monitoring in blood serum is vital due to its narrow therapeutic window. Accordingly, WA determination has been conducted using various methods, such as high-performance liquid chromatography, fluorescent, surface-enhanced Raman scattering, and electrochemical methods. Electrochemical methods have received considerable attention due to their outstanding selectivity, remarkable sensitivity, great time efficiency, and cost-effectiveness. Herein, a comprehensive literature survey on electrochemical methods for determining WA is presented. This review discusses the development of various chemically modified electrodes (CMEs). These CMEs, such as multi-wall carbon nanotubes, molecularly imprinted polymers, metal oxide nanoparticles, and polymer nanocomposites, owing to their morphology and structure, high selectivity, high conductivity, and high volume/area ratio, are designed to overcome the limitations of bare electrodes, which include reduced electrocatalytic activity, slower electron transfer rates, and poor sensitivity. Also, this review presents the advantages and disadvantages of various modified electrodes applied in WA detection.

Enantioselective electrochemical detection of a L-and D-serine at polyvinylpyrrolidone-modified platinum electrode

Aim: By modifying the Pt electrode with polyvinylpyrrolidone, the distinct oxidation potentials of L and D-serine were markedly increased for both isomers.Methods & results: CV was used for Pt electrode modification with PVP. Twenty cycles was reasonable for Pt modification. K3[Fe(CN)6] CV experiments investigated reversibility of the Fe(III) redox reaction and the enhancement of electron transfer at the PVP-Pt electrode. L and D-serine showing an oxidation peak potential at 0.394 V and 0.468 V, respectively. A linear relationship between the anodic oxidation current extracted from the CVs and the standard concentrations of L-serine and D-serine solutions was obtained with R2 = 0.99. The dynamic range for D-serine was from 0.5 to 20 mM with a LOD of 0.16 mM, while for L-serine, was from 2.5 to 20 mM with a detection limit of 0.27 mM. Using DPV, the dynamic range was 0.05-1.0 µM for D-serine with a detection limit of 0.0103 µM. The standard deviation ranged from 0.212 to 0.38 across ten determinations per concentration.Conclusion: A separation by 74 mV between the oxidation peaks of L and D-serine was achieved with remarkable enhancement in oxidation current for both isomers. PVP-Pt electrode can detect D-serine in the presence of DL-serine.

Nanomaterial-Based Sensors for Coumarin Detection

Sensors are widely used owing to their advantages including excellent sensing performance, user-friendliness, portability, rapid response, high sensitivity, and specificity. Sensor technologies have been expanded rapidly in recent years to offer many applications in medicine, pharmaceuticals, the environment, food safety, and national security. Various nanomaterial-based sensors have been developed for their exciting features, such as a powerful absorption band in the visible region, excellent electrical conductivity, and good mechanical properties. Natural and synthetic coumarin derivatives are attracting attention in the development of functional polymers and polymeric networks for their unique biological, optical, and photochemical properties. They are the most abundant organic molecules in medicine because of their biological and pharmacological impacts. Furthermore, coumarin derivatives can modulate signaling pathways that affect various cellular processes. This review covers the discovery of coumarins and their derivatives, the integration of nanomaterial-based sensors, and recent advances in nanomaterial-based sensing for coumarins. This review also explains how sensors work, their types, their pros and cons, and sensor studies for coumarin detection in recent years.

Therapeutic drug monitoring of six contraindicated/co-administered drugs by simple and green RP-HPLC-PDA; application to spiked human plasma

Therapeutic drug monitoring is an important clinical testing of the drugs to monitor their concentrations in plasma in order to guarantee their optimal impact, and to avoid any side effects resulting from drug-drug interactions. A green reversed-phase high-performance liquid chromatographic method using a photodiode array detector (RP-HPLC-PDA) was developed for the simultaneous determination of three carbapenem antibiotics (Imipenem, ertapenem, and meropenem) with the co-formulated drug (cilastatin) and contraindicated drugs (probenecid and warfarin) in spiked human plasma. The separation was achieved at 25 °C using a gradient elution of a mixture of mobile phase A: methanol and mobile phase B: phosphate buffer (pH 3.0). The photodiode array detector was adjusted at 220 nm. Bioanalytical method validation was carried out as per the FDA guidelines, and the method showed good linearity ranges for the six drugs that included their Cmax levels along with low limits of quantification. Based on the results, the method was found to be accurate and precise; with high % recovery and good % RSD, respectively. The method was successfully applied to spiked human plasma, signifying a good potential to be implemented in future TDM studies of these drugs when co-administered together.

Enantioselective voltammetric sensor based on mesoporous graphitized carbon black Carbopack X and fulvene derivative

For medicine and pharmaceuticals, the problem of determining and recognizing the enantiomers of biologically active compounds is an actual issue because the enantiomers of the same substance can have different effects on living organisms. This paper describes the development of an enantioselective voltammetric sensor (EVS) based on a glassy carbon electrode (GCE) modified with mesoporous graphitized carbon black Carbopack X (CpX) and a fulvene derivative (1S,4R)-2-cyclopenta-2,4-dien-1-ylidene-1-isopropyl-4-methylcyclohexane (CpIPMC) for recognition and determination of tryptophan (Trp) enantiomers. Synthesized CpIPMC was characterized by 1 H and 13 C nuclear magnetic resonance (NMR), chromatography-mass spectrometry, and polarimetry. The proposed sensor platform was studied by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Using the square-wave voltammetry (SWV), it was established that the developed sensor is an effective chiral platform for the quantitative determination of Trp enantiomers, including in a mixture and in biological fluids like urine and blood plasma, with adequate precision and recovery ranged from 96% to 101%.

Enantioseparation/Recognition based on nano techniques/materials

Enantiomers show different behaviors in interaction with the chiral environment. Due to their identical chemical structure and their wide application in various industries, such as agriculture, medicine, pesticide, food, and so forth, their separation is of great importance. Today, the term "nano" is frequently encountered in all fields. Technology and measuring devices are moving towards miniaturization, and the usage of nanomaterials in all sectors is expanding substantially. Given that scientists have recently attempted to apply miniaturized techniques known as nano-liquid chromatography/capillary-liquid chromatography, which were originally accomplished in 1988, as well as the widespread usage of nanomaterials for chiral resolution (back in 1989), this comprehensive study was developed. Searching the terms "nano" and "enantiomer separation" on scientific websites such as Scopus, Google Scholar, and Web of Science yields articles that either use miniaturized instruments or apply nanomaterials as chiral selectors with a variety of chemical and electrochemical detection techniques, which are discussed in this article.

Rational design of highly enantioselective composite voltammetric sensors using a computationally predicted chiral modifier

The use of chiral modifiers is among the simplest and most popular strategies for synthesizing enantioselective voltammetric sensors that are applied for the analysis and discrimination of enantiomerical drugs in various media. The type and structure of the chiral modifier are the key factors for the creation of enantioselectivity to a specified analyte. We suggest a novel approach to the prediction of the quality of a chiral modifier for preparing highly enantioselective sensors. The suggested approach is based on the molecular mechanics modeling of the adsorption of analyte enantiomers on chiral modifiers and on the comparison of the corresponding adsorption energies (ΔE_ads ). The efficiency of our approach is demonstrated using the example of cyclodextrins and chiral single-wall carbon nanotubes as chiral modifiers, and a wide range of chiral analytes. We found that the experimental enantioselectivity (ϑ_exp ) measured using voltammetry linearly correlates with ΔE_ads . The suggested approach also showed good predictive power in application to enantioselective chromatography, which further validates its general applicability.

Chiral Selectors in Voltammetric Sensors Based on Mixed Phenylalanine/Alanine Cu(II) and Zn(II) Complexes

A practical application composite based on mixed chelate complexes [M(S-Ala)2(H2O)n]–[M(S-Phe)2(H2O)n] (M = Cu(II), Zn(II); n = 0–1) as chiral selectors in enantioselective voltammetric sensors was suggested. The structures of the resulting complexes were studied by XRD, ESI-MS, and IR- and NMR-spectroscopy methods. It was determined that enantioselectivity depends on the metal nature and on the structure of the mixed complex. The mixed complexes, which were suggested to be chiral selectors, were stable under the experimental conditions and provided greater enantioselectivity in the determination of chiral analytes, such as naproxen and propranolol, in comparison with the amino acids they comprise. The best results shown by the mixed copper complex [Cu(S-Ala)2]–[Cu(S-Phe)2] were: ipS/ipR = 1.27 and ΔEp = 30 mV for Nap; and ipS/ipR = 1.37 and ΔEp = 20 mV for Prp. The electrochemical and analytical characteristics of the sensors and conditions of voltammogram recordings were studied by differential pulse voltammetry. Linear relationships between the anodic current and the concentrations of Nap and Prp enantiomers were achieved in the range of 2.5 × 10−5 to 1.0 × 10−3 mol L−1 for GCE/PEC-[Cu(S-Ala)2]–[Cu(S-Phe)2] and 5.0 × 10−5 to 1.0 × 10−3 for GCE/PEC–[Zn(S-Ala)2(H2O)]–[Zn(S-Phe)2(H2O)], with detection limits (3 s/m) of 0.30–1.24 μM. The suggested sensor was used to analyze Nap and Prp enantiomers in urine and plasma samples.

Carbon Nanomaterial-Based Drug Sensing Platforms Using State-of-the- Art Electroanalytical Techniques

Background:

Currently, nanotechnology and nanomaterials are considered as the most popular and outstanding research subjects in scientific fields ranging from environmental studies to drug analysis. Carbon nanomaterials such as carbon nanotubes, graphene, carbon nanofibers etc. and non-carbon nanomaterials such as quantum dots, metal nanoparticles, nanorods etc. are widely used in electrochemical drug analysis for sensor development. Main aim of drug analysis with sensors is developing fast, easy to use and sensitive methods. Electroanalytical techniques such as voltammetry, potentiometry, amperometry etc. which measure electrical parameters such as current or potential in an electrochemical cell are considered economical, highly sensitive and versatile techniques.

Methods:

Most recent researches and studies about electrochemical analysis of drugs with carbon-based nanomaterials were analyzed. Books and review articles about this topic were reviewed.

Results:

The most significant carbon-based nanomaterials and electroanalytical techniques were explained in detail. In addition to this; recent applications of electrochemical techniques with carbon nanomaterials in drug analysis was expressed comprehensively. Recent researches about electrochemical applications of carbon-based nanomaterials in drug sensing were given in a table.

Conclusion:

Nanotechnology provides opportunities to create functional materials, devices and systems using nanomaterials with advantageous features such as high surface area, improved electrode kinetics and higher catalytic activity. Electrochemistry is widely used in drug analysis for pharmaceutical and medical purposes. Carbon nanomaterials based electrochemical sensors are one of the most preferred methods for drug analysis with high sensitivity, low cost and rapid detection.