Simultaneous determination of methadone and morphine at a modified electrode with 3D β-MnO2 nanoflowers: application for pharmaceutical sample analysis

Electrochemical DNA-nano biosensor for the detection of Goserelin as anticancer drug using modified pencil graphite electrode

Goserelin is an effective anticancer drug, but naturally causes several side effects. Hence the determination of this drug in biological samples, plays a key role in evaluating its effects and side effects. The current studies have concentrated on monitoring Goserelin using an easy and quick DNA biosensor for the first time. In this study, copper(II) oxide nanoparticles were created upon the surface of multiwalled carbon nanotubes (CuO/MWCNTs) as a conducting mediator. The modified pencil graphite electrode (ds-DNA/PA/CuO/MWCNTs/PGE) has been modified with the help of polyaniline (PA), ds-DNA, and CuO/MWCNTs nanocomposite. Additionally, the issue with the bio-electroanalytical guanine oxidation signal in relation to ds-DNA at the surface of PA/CuO/MWCNTs/PGE has been examined to determination Goserelin for the first time. It also, established a strong conductive condition to determination Goserelin in nanomolar concentration. Thus, Goserelin's determining, however, has a 0.21 nM detection limit and a 1.0 nM-110.0 µM linear dynamic range according to differential pulse voltammograms (DPV) of ds-DNA/PA/CuO/MWCNTs/PGE. Furthermore, the molecular docking investigation highlighted that Goserelin is able to bind ds-DNA preferentially and supported the findings of the experiments. The determining of Goserelin in real samples has been effectively accomplished in the last phase using ds-DNA/PA/CuO/MWCNTs/PGE.

Machine learning-enhanced drug testing for simultaneous morphine and methadone detection in urinary biofluids

The simultaneous identification of drugs has considerable difficulties due to the intricate interplay of analytes and the interference present in biological matrices. In this study, we introduce an innovative electrochemical sensor that overcomes these hurdles, enabling the precise and simultaneous determination of morphine (MOR), methadone (MET), and uric acid (UA) in urine samples. The sensor harnesses the strategically adapted carbon nanotubes (CNT) modified with graphitic carbon nitride (g-C3N4) nanosheets to ensure exceptional precision and sensitivity for the targeted analytes. Through systematic optimization of pivotal parameters, we attained accurate and quantitative measurements of the analytes within intricate matrices employing the fast Fourier transform (FFT) voltammetry technique. The sensor's performance was validated using 17 training and 12 test solutions, employing the widely acclaimed machine learning method, partial least squares (PLS), for predictive modeling. The root mean square error of cross-validation (RMSECV) values for morphine, methadone, and uric acid were significantly low, measuring 0.1827 µM, 0.1951 µM, and 0.1584 µM, respectively, with corresponding root mean square error of prediction (RMSEP) values of 0.1925 µM, 0.2035 µM, and 0.1659 µM. These results showcased the robust resiliency and reliability of our predictive model. Our sensor's efficacy in real urine samples was demonstrated by the narrow range of relative standard deviation (RSD) values, ranging from 3.71 to 5.26%, and recovery percentages from 96 to 106%. This performance underscores the potential of the sensor for practical and clinical applications, offering precise measurements even in complex and variable biological matrices. The successful integration of g-C3N4-CNT nanocomposites and the robust PLS method has driven the evolution of sophisticated electrochemical sensors, initiating a transformative era in drug analysis.

Surface modification of a screen-printed electrode with a flower-like nanostructure to fabricate a guanine DNA-based electrochemical biosensor to determine the anticancer drug pemigatinib

The present study developed a DNA biosensor to determine pemigatinib for the first time. Three-dimensional carnation flower-like Eu3+:β-MnO2 nanostructures (3D CF-L Eu3+:β-MnO2 NSs) and a screen-printed electrode (SPE) modified with polyaniline (PA) were employed. The double-stranded DNA was also immobilized completely on the PA/3D CF-L Eu3+:β-MnO2 NSs/SPE. Then, electrochemical techniques were used for characterizing the modified electrode. After that, the interaction between pemigatinib and DNA was shown by a reduction in the oxidation current of guanine using differential pulse voltammetry (DPV). According to the analysis, the dynamic range of pemigatinib was between 0.001 and 180.0 μM, indicating the new electrode has a low limit of detection (LOD = 0.23 nM) for pemigatinib. Afterwards, pemigatinib in real samples was measured using the PA/3D CF-L Eu3+:β-MnO2 NSs/SPE loaded with ds-DNA. The proposed DNA biosensor showed good selectivity toward pemigatinib in the presence of other interference analytes, such as other ions, structurally related pharmaceuticals, and plasma proteins. In addition, the interaction site of pemigatinib with DNA was predicted by molecular docking, which showed the interaction of pemigatinib with the guanine bases of DNA through a groove binding mode. Finally, we employed the t-test to verify the capability of the ds-DNA/PA/3D CF-L Eu3+:β-MnO2 NSs/SPE for analyzing pemigatinib in real samples.

A nanoscale electrochemical guanine DNA-biosensor based on a flower-like nanocomposite of Tb-doped ZnO for the sensitive determination of pemetrexed

Pemetrexed is an antineoplastic drug used in chemotherapeutic treatments, especially in malignant mesothelioma and non-small cell lung carcinoma, but can also cause a variety of complications, like stomach pain, nausea, burning, vomiting, numbness, and tingling, emphasizing the need for an approach to quantify the drug in biological matrices. Herein, a DNA-based biosensor was introduced for pemetrexed determination. A hydrothermal approach was used for synthesizing flower-like nanoparticles (NPs) of zinc oxide (ZnO) doped with Tb (FL-NP Tb3+/ZnO). Moreover, energy dispersive X-ray (EDX), field-emission scanning electron microscopy (FESEM), zeta potential, Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD) analyses were used for characterizing the as-prepared nanocomposite. According to the impedance analysis, FL-NP Tb3+/ZnO was accompanied by very good electrochemical functions for a simple transfer of electrons. In the case of the immobilization of double-stranded deoxyribonucleic acid (ds-DNA) on the FL-NP Tb3+/ZnO and polypyrrole (PP)-modified pencil graphite electrode (ds-DNA/PP/FL-NP Tb3+/ZnO/PGE), a considerable enhancement was found in the electrochemical oxidation of guanine in ds-DNA residue bases. Since there was an interaction between ds-DNA and pemetrexed, the voltammetric current of guanine over the ds-DNA/PP/FL-NP Tb3+/ZnO/PGE declined in the presence of pemetrexed in the electrolytic solution. Moreover, under optimum conditions (25 mg L-1 of ds-DNA and 10 min incubation time, in acetate buffer at 25 °C), a linear decrease in the guanine signal was observed on the ds-DNA/PP/FL-NP Tb3+/ZnO/PGE as the pemetrexed concentration increased in the range from 0.001 μM to 175.0 μM with a limit of detection of 0.17 nM. Finally, the new DNA-based biosensor was successfully used for determining pemetrexed in real samples, indicating its application potential.

Electrochemical detection of kynurenic acid in the presence of tryptophan with the carbon paste electrode modified with the flower-like nanostructures of zinc oxide doped with terbium

With the help of a hydrothermal approach in this study, we could provide flower-like nanostructures (NSs) of zinc oxide (ZnO) doped with Tb (FL-NS Tb3+/ZnO). Then, FL-NS Tb3+/ZnO morphology was investigated by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and map analysis. The results revealed higher activity centers and porosity of this nanocomposite, which were followed by acceptable electrochemical function. Hence, it can be utilized for fabricating an electrochemical sensor with an appropriate response for the simultaneous determination of kynurenic acid (KYN) and tryptophan (TRP). However, as compared with the modified carbon paste electrode (FL-NS Tb3+/ZnO/CPE), the bare carbon paste electrode (BCPE) exhibited a weak response toward KYN and TRP but the modified electrode was followed by a high current response for KYN and TRP at a potential 0.35 and 0.809 V. Therefore, cyclic voltammetry (CV) was applied in optimal experimental conditions to study the electrochemical behaviors of KYN and TRP over the surface of the proposed modified electrode. Moreover, we used differential pulse voltammetry (DPV) for quantitative measurements. It was found that this new modified electrode linearly ranged from 0.001 to 700.0 μM, with detection limits of 0.34 nM and 0.22 nM for KYN and TRP, respectively. In addition, KYN and TRP in real samples can be analyzed by this sensor, with a recovery of 97.75%-103.6% for the spiked KYN and TRP in real samples.

MXene-based composites as an electrochemical sensor for ultrasensitive determination of ofloxacin

Sensitive determination of ofloxacin (OFL) is very essential for human health and environmental protection. Here, a novel composite of gold nanoparticles(nAu)@MXene(Ti₃C₂T_x)/poly-p-aminobenzene sulfonic acid (PABSA) was fabricated on the surface of glassy carbon electrode (GCE) and used to sensitively determine OFL. The results of experiments showed that the obtained nAu@Ti₃C₂T_x/PABSA/GCE electrode could be used as an electrochemical sensor to directly detect ofloxacin (OFL) by differential pulse voltammetry (DPV). Under the optimal conditions, the proposed electrode displayed a broader linear range and a lower detection limit (LOD) for OFL determination when it was compared to those similar sensors. The linear range was from 5.0 × 10^-8 to 5.0 × 10^-4 mol/L and the LOD was 3.7 × 10^-8 mol/L (S/N = 3). The nAu@Ti₃C₂T_x/PABSA/GCE electrode also showed good selectivity, repeatability, and reproducibility. Finally, the proposed electrode was used to detect OFL in commercial samples by the standard addition method. The obtained recovery was from 97.3% and 105.7% showing its potential applications in actual sample analysis.

Analytical Approaches for the Determination of Buprenorphine, Methadone and Their Metabolites in Biological Matrices

The abuse of buprenorphine and methadone has grown into a rising worldwide issue. After their consumption, buprenorphine, methadone and their metabolites can be found in the human organism. Due to the difficulty in the assessment of these compounds by routine drug screening, the importance of developing highly sensitive analytical approaches is undeniable. Liquid chromatography tandem mass spectrometry is the preferable technique for the determination of buprenorphine, methadone and their metabolites in biological matrices including urine, plasma, nails or oral fluids. This research aims to review a critical discussion of the latest trends for the monitoring of buprenorphine, methadone and their metabolites in various biological specimens.

Simultaneous electrochemical determination of morphine and methadone by using CMK-5 mesoporous carbon and multivariate calibration

For the first time, a sensitive electrochemical sensor using a glassy carbon electrode modified with CMK-5 Ordered mesoporous carbon was fabricated for simultaneous analysis of morphine and methadone. Modern electrochemical FFT-SWV techniques and partial least-squares as a multivariable analysis were used in this method. CMK-5 nanostructures were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. Variables such as accumulation time and pH for the proposed sensor were optimized before quantitative analysis. To train the proposed sensor, standard mixtures of morphine (MOR), and methadone (MET) were prepared in the established linear ranges of the analyzes. The results obtained from training samples were used for PLS modeling. The efficiency of the model was determined using test and real matrix samples. The root mean square error of prediction and the squared correlation coefficients (R²_p) for MET and MOR were estimated to be 0.00772 and 0.00892 and 0.948 to 0.990, respectively. The recoveries in urine samples were reported to be 97.0 and 105.6% for both MOR and MET, respectively.

Advances of Drugs Electroanalysis Based on Direct Electrochemical Redox on Electrodes: A Review

The strong development of mankind is inseparable from the proper use of drugs, and the electroanalytical research of drugs occupies an important position in the field of analytical chemistry. This review mainly elaborates the research progress of drugs electroanalysis based on direct electrochemical redox on various electrodes for the recent decade from 2011 to 2021. At first, we summarize some frequently used electrochemical data processing and electrochemical mechanism research derivation methods in the literature. Then, according to the drug therapeutic and application/usage purposes, the research progress of drugs electrochemical analysis is classified and discussed, where we focus on drugs electrochemical reaction mechanism. At the same time, the comparisons of electrochemical sensing performance of the drugs on various electrodes from recent studies are listed, so that readers can more intuitively compare and understand the electroanalytical sensing performance of each modified electrode for each of the drug. Finally, this review discusses the shortcomings and prospects of the drugs electroanalysis based on direct electrochemical redox research.

Progress in pretreatment of methadone: an update since 2015

Methadone, a µ-opioid receptor agonist, is widely used in pain-relieving and treating opioid dependence. If not strictly controlled, as an opioid substitute, it can lead to abuse and cause more severe withdrawal responses than heroin. Also, overdose or abuse of this drug in clinical use may provide severe side effects such as apnea, circulatory collapse, cardiac arrest, and even death. For these reasons, simple, rapid, and efficient methods have been developed for the pretreatment of methadone. This review presents a comprehensive conclusion of the pretreatment methods used for methadone in various sample matrices, focusing on the developments since 2015. Traditionally used pretreatment methods like solid-phase extraction and liquid-liquid extraction are discussed and newly developed methods like solid-phase microextraction and liquid-liquid microextraction along with new materials applied are focused.