Pharmaceutical Samples Research Articles

Novel disposable screen-printed sensors based on copper oxide nanoparticles for sensitive voltammetric assay of antazoline

The fabrication and electroanalytical validation of a novel homemade screen-printed carbon electrode enriched with copper oxide nanoparticles (CuONPs/SPCEs) were demonstrated for sensitive and selective voltammetric determination antazoline (ANT) in eye drop solution and spiked serum samples. With a reported electrocatalytic activity, CuONPs catalyzed the oxidation of ANT at the electrode surface showing an irreversible anodic oxidation peak at 0.9 V under a diffusion-controlled electrode reaction. Based on the electroanalytical and molecular orbital calculation studies, oxidation of ANT molecule undergoes via oxidation of the aliphatic nitrogen atom within the ANT moiety. Linear calibration curves were illustrated covering the ANT concentration ranged from 0.01 to 3.819 µg mL−1 with and limit of detection 3 ng mL−1. The fabricated sensors enriched with CuONPs exhibited high fabrication and measurement reproducibility with a prolonged shelf lifetime (6 months). The electroanalytical approach presented adequate sensitivity and selectivity with a short analysis time, applying low-cost instrumentation and simple pretreatment protocol avoiding handling hazardous organic solvents. Trace ANT was monitored in the presence of different interfering species, degradation products, and xylometazoline hydrochloride (ZYL) in the co-formulated ophthalmic pharmaceutical samples. The CuONPs based voltammetric sensors were introduced as a reliable eco-friendly analytical tool for monitoring ANT in ophthalmic solutions and biological fluids with acceptable recovery values.

Facile and green chemistry-compatible fluorescence spectroscopic applications of acid red 87 used to evaluate eletriptan, antimigraine, in its pharmaceutical and biological samples

Eletriptan (ETR), a selective pharmaceutical agent agonist of the 5-hydroxytryptamine1 receptor subtype, are primarily used to treat acute migraine attacks. ETR is a triptan-class medication that works by narrowing cerebral blood vessels and reducing chemicals that produce headache pain, light and sound sensitivity, and nausea. Due to its effectiveness in reducing migraine symptoms, it is a worthwhile choice for those looking for quick and efficient treatment. A green, raid, one-pot and straightforward fluorescence spectrometric method was employed to evaluate ETR in tablets and biological samples. By introducing the ETR drug and the fluorescent ligand, Acid red 87, in an acidic buffer, a quenching of the ligand native fluorescent was promptly produced. The quenching action was simply attributed to the selective ion-pair complex generation between the cationic target and the selected ligand. An increase in ETR concentration was linearly proportional to the quenching response in the 50.0 – 500.0 ng/mL range. The optimal configurations for adjusting the system's variable parameters were determined by examining the ETR–Acid red 87 system's response. Additionally, the sensor that was developed met the standards set by the International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use. The sensitivity thresholds of the approach were 13.8 and 42.0 ng/mL for the detection and quantification parameters, respectively, LOD and LOQ. This approach proficiently evaluated the pharmaceutical and biological samples of ETR. Finally, the proposed approach not only simplifies the analysis process but also limits the badimpact on the environment, making it a promising technique for analytical applications.

Synthesis of oxygen vacancies rich CeO2-xNx/GCN hybrid nanostructure with great active interfaces for electrochemical detection of antiviral levofloxacin in pharmaceutical samples

COVID-19 is an emerging viral infectious disease. Severe respiratory problems are considered an important syndrome of COVID-19 in humans. Levofloxacin (LEV), a promising fluoroquinolone antibacterial agent/therapeutic agent for influenza virus (H1N1)-induced pneumonia drug. These have been used as a potent antidote for acute respiratory tract infections. Owing to its excellent pharmacokinetic properties such as potential antiviral and scavenging activity, LEV has been used in controlling and treating COVID-19 during infectious emergencies. Even taking over the dosage of LEV and disposing of the embryonic toxic nature of LEV residues in the pharmaceutical research industry can cause adverse effects on the public health and environment. For this purpose, the development of great analytical tools is important to the detection of antiviral LEV for human health safety and environmental protection. In this work, we report a nitrogen (N) doped strategy to construct the enriched oxygen vacancies (OVs) on CeO2-xNx/GCN-2 hybrid nanostructure as an efficient electrocatalyst for the ultrasensitive detection of antiviral LEV. The effect of the N doping into the CeO2 (CeO2-xNx) lattice with increasing the large amount of OVs and boosted their redox properties (Ce4+→Ce3+), thus provided that a great electrochemically active site. Although the abundant OVs were conformed on the CeO2-xNx/GCN-2 from the peak-area ratio of Ce3+/Ce4+ and O2/O1 by X-ray photoelectron spectroscopy (XPS) assay. Owing to the strong electronic coupling between the OV-rich CeO2-xNx and the conductive GCN surface, thus CeO2-xNx/GCN-2 heterojunction achieved superior analytical performance for LEV oxidation with a good linear range from 0.01 μM to 710 μM, and detection limits of 5.6 nM (S/N = 3), and sensitivity 24.711 μA μM−1 cm−2 at a very low working potential (0.7 V). The proposed hybrid sensor also exploited to the analysis of the pharmaceutical industry wastewater, pharmaceutical tablet and human urine samples with a satisfactory recovery rate.

Synthesis of Zinc Oxide Nanoparticles Based on Coffee Husks Embedded on Mesoporous Silica for the Sensing of Acetaminophen

AbstractIn the present work, a green method improved by surface response methodology (SRM) has been used for the synthesis of zinc oxide nanoparticles (ZnONPs) from coffee husks extract, in which Santa Barbara‐15 (SBA‐15) mesoporous silica has been embedded. The composite formed has been drop coated on bare glassy carbon electrode and the resulting sensor (ZnONPs/SBA‐15/GCE) was used for the sensing of acetaminophen (ACT). Reaction factors such as pH, incubation time and precursor concentration were optimized during nanoparticles synthesis using SRM. The synthesized nanoparticles and the composite were characterized by ultraviolet‐visible spectrophotometry (UV‐Vis), Fourier transform infrared (FTIR) spectroscopy, powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX/EDX‐mapping) analysis, thermogravimetry analysis/differential thermogravimetry (TGA/DTG), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), showing the good elaboration of ZnONPs/SBA‐15/GCE. After optimization of parameters susceptible to affect the detection limit of ACT, the calibration curve was plotted from 4 μM to 32 μM, showing good linear response with a detection limit of 0.11 μM. The developed sensor shows good sensitivity, reproducibility, repeatability and storage stability at room temperature and was successfully applied for the determination of ACT in pharmaceutical sample.

Novel sample double dilution calibration method for determination of lithium in biological samples using automatic flow system with in-syringe reaction

A novel sample double dilution calibration method (SDDCM) and an automatic flow system with in-syringe reaction and spectrophotometric detection were developed for determining lithium in biological samples. The method is based on the reaction of lithium with Thorin in an alkaline medium and the signal was measured at 480 nm. The reaction was performed simultaneously for both standards and samples in three syringes of the automatic flow system. The method was validated and successfully applied to the determination of lithium in synthetic and pharmaceutical samples, with results consistent with the ICP OES method. The novel calibration method, developed for the determination of lithium in biological samples, uses a sample with two dilution degrees. Using the method, the concentration of the analyte is determined by relating the signal for a less diluted sample to the calibration plot for a more diluted sample and vice versa. The implementation of the calibration method was facilitated by preparing solutions directly in the flow system. The use of two sample dilutions makes it possible to determine the analyte in the sample without preliminary preparation. Moreover, obtaining two results based on signals for a sample diluted to different degrees allows them to be verified for accuracy. The proposed approach was successfully verified by the determination of lithium in certified reference materials of blood serum and urine. Using the developed method lithium was determined within the concentration range of 0.06–1.5 mg L−1, with precision (CV, %) less than 6.7, and accuracy (RE, %) better than 6.9. The detection limit was 0.03 mg L−1.

Development of an orbital shaker-assisted fatty acid-based switchable solvent microextraction procedure for rapid and green extraction of amoxicillin from complex matrices: Central composite design

In this study, a cheap, fast and simple orbital shaker-assisted fatty acid-based switchable solvent microextraction (OS-FASS-ME) procedure was developed for the extraction of amoxicillin (AMOX) in dairy products, pharmaceutical samples and wastewater prior to its spectrophotometric analysis. Fatty acid-based switchable solvents were investigated for extracting AMOX. The key factors of the OS-FASS-ME procedure were optimized using a central composite design. The linearity of OS-FASS-ME procedure was in the range 5–600 ng mL−1 with a correlation coefficient of 0.991. In five replicate experiments for 20 ng mL−1 of AMOX solution, the recovery and relative standard deviation were 95.8% and 2.2%, respectively. Limits of detection and quantification were found 1.5 ng mL−1 and 5 ng mL−1, respectively. The accuracy, precision, robustness and selectivity of the OS-FASS-ME procedure were investigated in detail under optimum conditions. The OS-FASS-ME procedure was applied to milk, cheese, wastewater, syrups and tablets. A comparison of the results obtained from the reference method and the OS-FASS-ME method showed that the OS-FASS-ME procedure can be successfully applied to complex matrices.

Green Electrochemical Sensing: Novel Ion-Selective Electrode Method for Precise Determination of Dimenhydrinate and its Metabolite along with Cinnarizine in Pharmaceutical and Plasma Samples

Green and sustainable scientific research is crucial for health and environmental improvement. Electrochemical analysis simplifies complex processes, saving time and cost. Ion selective electrode method, a key in green analytical chemistry, was utilized. A highly selective solid contact sensor was developed for two applications, detecting cinnarizine (CIN) and dimenhydrinate (DMH) in pharmaceuticals, and identifying CIN and diphenhydramine (DIP) in human plasma. Careful selection of ionophores ensured accurate detection. Multi-wall carbon-nanotubes (MWCNTs) facilitate rapid and precise measurement. The concentration range for CIN, DMH, and DIP was 1 × 10−6 M to 1 × 10−2 M, with mean recovery% of 100.07 ± 0.80, 100.12 ± 0.76, and 100.07 ± 0.53, respectively. Validation parameters exhibited accuracy and precision, with accuracy results of 100.87 ± 0.89, 99.96 ± 0.42, and 99.82 ± 0.31, and LODs of 0.5 × 10−6, 1.0 × 10−7, and 0.2 × 10−6 for CIN, DMH, and DIP, respectively. The study highlighted benefits like speed, economy, and sustainability, emphasizing the electrode’s reusability. SWOT analysis and environmental assessments further underscored its advantages, promising applications in pharmaceutical analysis and quality control.

Electrochemical determination of theophylline using a nickel ferrite/activated carbon-modified electrode

In this work, a nanocomposite based on nickel ferrite/activated carbon (NiF/AC) was used to modify a highly sensitive electrochemical sensor for the quantification of theophylline (TPL) in pharmaceutical tablets. The synthesized materials were characterized using x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy-elemental mapping and surface area analysis via the Brunauer–Emmett–Teller method. Cyclic voltammetry was employed to study the electrocatalytic properties of the NiF/AC-GCE toward the oxidation of TPL. The dependence of the electrochemical response on the scan rate and pH was also investigated, and the working parameters were optimized. The linear range of the established electrochemical biosensor was from 0.5 to 5 μM (R2 = 0.997), with a detection limit of 0.21 μM. The present method was tested using three pharmaceutical formulation standard samples with good accuracy and acceptable recovery. Thus, it is a promising candidate for the determination of TPL in pharmaceutical formulations.

Electrochemical Detection of Melphalan in Biological Fluids Using a g-C3N4@ND-COOH@MoSe2 Modified Electrode Complemented by Molecular Docking Studies with Cellular Tumor Antigen P53.

Melphalan (Mel) is a potent alkylating agent utilized in chemotherapy treatments for a diverse range of malignancies. The need for its accurate and timely detection in pharmaceutical preparations and biological samples is paramount to ensure optimized therapeutic efficacy and to monitor treatment progression. To address this critical need, our study introduced a cutting-edge electrochemical sensor. This device boasts a uniquely modified electrode crafted from graphitic carbon nitride (g-C3N4), decorated with activated nanodiamonds (ND-COOH) and molybdenum diselenide (MoSe2), and specifically designed to detect Mel with unparalleled precision. Our rigorous testing employed advanced techniques such as cyclic voltammetry and differential pulse voltammetry. The outcomes were promising; the sensor consistently exhibited a linear response in the range of 0.5 to 12.5 μM. Even more impressively, the detection threshold was as low as 0.03 μM, highlighting its sensitivity. To further enhance our understanding of Mel's biological interactions, we turned to molecular docking studies. These studies primarily focused on Mel's interaction dynamics with the cellular tumor antigen P53, revealing a binding affinity of -5.0 kcal/mol. A fascinating observation was made when Mel was covalently conjugated with nanodiamond-COOH (ND-COOH). This conjugation resulted in a binding affinity that surged to -10.9 kcal/mol, clearly underscoring our sensor's superior detection capabilities. This observation also reinforced the wisdom behind incorporating ND-COOH in our electrode design. In conclusion, our sensor not only stands out in terms of sensitivity but also excels in selectivity and accuracy. By bridging electrochemical sensing with computational insights, our study illuminates Mel's intricate behavior, driving advancements in sensor technology and potentially revolutionizing cancer therapeutic strategies.

A highly sensitive electrochemical sensing platform to detect rutin in pharmaceutical and serum samples

In this study, we created a brand-new g-C3N4-MWCNTs/Ag/β-CD-MOF electrode that can be used as a platform for the electrochemical sensing of Rutin (RT). The g-C3N4-MWCNTs/Ag/β-CD-MOF composite was synthesized via calcination treatment and electrodeposition, coupled with hydrothermal reaction. This composite could appreciably enlarge the electrochemically active surface area of the as-prepared sensor to promote electron transfer and result in the enhanced response signals.With the assistance of differential pulse voltammetry (DPV) and cyclic voltammetry (CV), the electrochemical performance of sensor can be greatly enhanced. Under these optimum conditions, the designed electrochemical sensor was able to sense RT at the lower detection limit (LOD) of 0.69 nM (S/N = 3) with a wider range of 5–500 nM and showed high sensitivity of 1.97 μA. nM−1. cm−2 at room temperature. Additionally, the selective investigation on RT was performed with the related interfering molecules, and the g-C3N4-MWCNTs/Ag/β-CD-MOF/GCE showed decent stability and reproducibility. The real-time application of the modified electrode for RT detection was monitored in both pharmaceutical and serum samples with the satisfactory recovery. Overall, this research contributes to the field of the electroanalytical sensing and offers the potential applications in the drug monitoring.

Chiral octahedral cobalt(III) complex immobilized on Carboblack C as a novel robust and readily available enantioselective voltammetric sensor for the recognition of tryptophan enantiomers in real samples

Enantioselective voltammetric sensors (EVSs) have significant interest in analytical and medicinal chemistry, as they allow for the express analysis and recognition of pharmacologically active components in drugs, as well as the establishment of the enantiopurity of compounds. The most common methods of modifying the electrode surface are through molecular imprinting techniques and the addition of a non-electroactive chiral modifier to the electrode composition. By varying the structure and properties of the chiral modifier, the sensor can be designed to have the highest enantioselectivity for a chosen chiral analyte. In this study, we describe the development of a new type of EVS based on a Carboblack C paste electrode modified with a chiral octahedral cobalt(III) complex for use as a selective enantioselector. It was found that the EVS, prepared from enantiopure Co(III) complexes, can selectively recognize L- and D-tryptophan (Trp) in phosphate buffer solution (PBS) with pH = 6.86. The peak current ratio (iD/iL) between the two enantiomers reached 1.36, demonstrating the effectiveness of the sensor. The experimental results indicate a linear correlation between the peak currents of Trp enantiomers and their concentration in the range from 1.00·10−6 to 5.00·10−4 М, leading to a detection limit of 2.42 µM and 3.30 µM for D- and L-Trp, respectively, when using chiral octahedral Co(III) complex with chloride counter-anion. Next, the EVSs developed demonstrated practical applicability in measuring the concentration of Trp in pharmaceutical samples and human urine and blood plasma. An important advantage of these sensors is the difference in the oxidation potentials between Trp enantiomers (ΔEp=35 mV), which makes it possible to determine Trp enantiomers in their mixtures. Quantum chemical calculations and experimental data show that the octahedral Co(III) complex binds to one of the Trp enantiomers with a stronger affinity, thus increasing its concentration at the electrode surface and promoting its oxidation. The easy preparation of the chiral Co(III) complex from inexpensive commercial materials, its high stability and insolubility in water make it a promising selector for the creation of efficient multifunctional EVSs for the analysis of various aqueous solutions.

Blending polydopamine-derived imprinted polymers with rice straw-based fluorescent carbon dots for selective detection and adsorptive removal of ibuprofen

Dual-functioning probes capable of detecting and removing hazardous substances have recently received increased attention compared to exclusive sensory probes. Herein, a new composite is synthesized by blending polydopamine imprinted polymers with fluorescent carbon dots (PIP-FCDs) for the selective recognition and adsorption of Ibuprofen (IBF). IBF is a nonsteroidal anti-inflammatory drug and is excessively released in the pharmaceutical wastes. The PIP-FCDs consist of confined pockets for encasing IBF and quenches fluorescence signal when contact with the molecule. PIP-FCDs show high sensitivity (limit of detection = 1.58 × 10−5 μM) and selectivity towards IBF in the presence of other pharmaceutical drugs i.e., aspirin, ketoprofen, norfloxacin, and levofloxacin. The adsorption studies show an adsorption capacity of 209.8 mg g−1 with an extraction efficiency of around 99.9 %. Furthermore, PIP-FCDs are utilized to determine IBF levels in various aqueous pharmaceutical samples. This development provides a simple and dual-functioning probe for the detection and adsorption of IBF from various matrices.

Occurrence of Selected Pharmaceuticals in the East London Coastline Encompassing Major Rivers, Estuaries, and Seawater in the Eastern Cape Province of South Africa.

This study investigated the occurrence of ibuprofen, naproxen, sulfamethoxazole, trimethoprim, and efavirenz in water resources (river, estuarine, and sea waters) of the East London coastline, South Africa. These pharmaceuticals were previously reported to be dominant in wastewater and inland rivers of South Africa. Hence, it is important to monitor their occurrence in the coastal and marine environment. The pharmaceuticals of interest were extracted with a solid-phase extraction method and analyzed by using a liquid chromatography-quadrupole time-of-flight mass spectrometry instrument. The analytical method was validated by spiking the environmental samples with a mixture of pharmaceuticals at two concentration levels (5 and 15 μg L-1). The analytical method yielded acceptable recoveries ranging from 75 to 107%, with method quantitation limits from 0.16 to 9.44 ng of L-1. All five targeted pharmaceuticals were detected in seawater samples, with ibuprofen recording the highest concentration of 90 ng L-1. However, it was efavirenz and sulfamethoxazole with the highest concentrations of 572 and 60 ng L-1, respectively, in the Gonubie River that showed high ecotoxicological risks toward the aquatic organisms. There were no risks associated with the occurrence of other targeted pharmaceuticals. The suspect screening showed the occurrence of 57 additional pharmaceuticals in samples, with antibiotics being more dominant. The results of the present study demonstrate a need to perform a more robust investigation on the occurrence of a wide range of pharmaceuticals along the South African coasts.

Electrochemical sensing of acetaminophen in biofluids, pharmaceutical and environmental samples using cobalt hexacyanoferrate decorated iron terephthalate metal organic framework

Herein, a highly sensitive, cost-effective, and sustainable electrochemical sensor was developed for the selective sensing of acetaminophen (ACP) in actual samples using cobalt hexacyanoferrate (CHCF) incorporated iron terephthalate metal organic framework (FMF). The CHCF-FMF was sustainably synthesized and characterized using FTIR, XRD and SEM with EDX analysis. Using CHCF-FMF, a modified electrode was fabricated by drop-casting it over a glassy carbon, which on voltammetric investigations, revealed the presence of Co2+/3+ redox couple with a formal potential of 0.51 V. Further, the designed sensor was employed for the electrocatalytic oxidation of ACP, which showed a linear detection range from 0.05 to 7.37 mM with a sensitivity and detection limit of 100.64 µA/mM/cm2 and 13 µM, respectively. Furthermore, the developed CHCF-FMF/GCE sensing system is highly facile and robust, and it has demonstrated excellent stability, selectivity, repeatability, and good reproducibility. The superior performance was attributed to the in-situ formation of CHCF over FMF, which efficiently arranged them to augment the electrochemical and electrocatalytic properties. Besides, the sensor was employed to determine ACP in blood serum, commercial tablets, and environmental samples, which showed recovery ranges of 96.2% – 106.2%. This work provides a novel strategy for designing catalytically active sites at the molecular level, which opens a new avenue in fine-tuning MOFs for their applicability in medical diagnostics, point-of-care, industrial and environmental monitoring devices.

A Surfactant-Electropolymer modified dual sensor for the monitoring of norepinephrine at nanomolar levels in biological samples and pharmaceutical formulations

This paper focuses on the surface modification of a Glassy carbon electrode (GCE) using poly-terephthalic acid and poly-4-amino-3-hydroxy-1-naphthalenesulfonic acid (poly-(TERE-AHNSA)/GCE) by simultaneous electropolymerization of respective monomers for the first time from the best of our knowledge, which is a simple and cost-effective method. FTIR, AFM, and SEM-EDX examinations were used to confirm the developed electrode. The adapted electrode is then used for the monitoring and determination of clinically significant norepinephrine (NE) using electroanalytical techniques such as differential pulse and cyclic voltammetry. The electrooxidation of NE on poly-(TERE-AHNSA)/GCE occurred at a potential of +0.216 V in phosphate buffer solution (PB) of pH 6.0 and showed a higher current response compared to electrodes developed with separate electropolymers. This enhanced response is likely due to the synergistic effect of both polymer layers obtained through electropolymerization, which increases the surface area. The developed sensor exhibits favorable characteristics, including a lowest detection limit (LOD) of 2.08 nM, a linear range spanning from 5.0 nM to 1600.0 μM which is the widest range ever reported, as well as improved sensitivity and selectivity, surpassing previous reports. The linearity analysis was also performed utilizing a screen-printed electrode (SPE), yielding linear ranges of 100.0 nM–600.0 μM. With a recovery rate ranging from 98 to 105%, the developed sensor shows great potential as a reliable tool for electroanalysis of NE in blood, urine, and pharmaceutical samples.

Determination of the Mass Fractions of the Heavy Metals in the Recycled Cellulose Pulp.

In the process of paper recycling, certain amounts of metals can be found in the cellulose suspension, the source of which is mainly printing inks. The paper industry often uses different technologies to reduce heavy metal emissions. The recycling of laminated packaging contributes to the formation of sticky particles, which affects the concentration of heavy metals. This study aimed to determine the mass fraction of metals in the different phases of the deinking process to optimize the cellulose pulp's quality and design healthy correct packaging products. In this research, the deinking flotation of laminated and non-laminated samples was carried out by the Ingede 11 method. As a result of the study, the mass fractions of metals in cellulose pulp were divided into four groups according to the mass fraction's increasing value and the metals' increasing electronegativity. The quantities of metals were analyzed using Inductively Coupled Mass Spectrometry (ICP-MS). The separation of metals from cellulose pulp is influenced by the presence of adhesives and the electronegativity of the metal. The results of the study show that the recycling process removes certain heavy metals very well, which indicates the good recycling potential of pharmaceutical cardboard samples.

Determination of amoxicillin: A penicillin antibiotic in pharmaceutical dosage samples by spectrophotometric method

New coupling agents such as 2,4-toluene diamine or sulphanilamide for the determination of amoxicillin spectrophotometrically are described. These methods are straightforward based on the reaction of amoxicillin with diazotized products of 2,4-toluene diamine or sulphanilamide to produce coloured azo dyes with maximum absorption at 462 or 468 nm. Amoxicillin responds linearly from 1.2–24.8 or 1.8–32.0 mg mL–1 when coupled with diazotized 2,4-toluene diamine or sulphanilamide. The molar absorptivity and Sandell’s sensitivity of amoxicillin with 2,4-toluene diamine or amoxicillin with sulphanilamide azo dyes were 3.307 × 104 or 2.632 × 104 L mol–1 cm–1 and 1.105×10-2 or 1.388×10-2 mg cm-2, respectively. The regression equation, correlation coefficient (R2), detection limit and quantitation limit of amoxicillin with 2,4-toluene diamine or amoxicillin with sulphanilamide were evaluated. The percentage recoveries ranged from 97.00 to 100.50 with a relative standard deviation value was ± 0.98 to ± 1.85%. The method does not need temperature control or solvent extraction and has been applied successfully to determine amoxicillin in pharmaceutical preparation (tablets).

Biowaste-derived carbon nanomaterial-based sensor for the electrochemical analysis of mefenamic acid in the presence of CTAB

Biomass waste can produce valuable products that offer significant economic and environmental benefits. Rice husk is a widely examined agricultural waste due to its lignin, cellulose, and hemicellulose composition, making it suitable for large-scale manufacturing. Because of their special physicochemical, electrical, optical, mechanical, thermal, and biocompatibility qualities, carbon nanomaterials made from rice husk have a wide range of uses in many industries. This study aims to showcase the green synthesis of graphene from rice biomass waste and its potential applications in biomedical research. Researchers used rice husk-derived graphene-modified carbon paste electrode (RHG/CPE) to detect mefenamic acid, a non-steroidal anti-inflammatory drug known to cause harm to patients at higher dosages and listed as a chemical pollutant. The sensor developed using this graphene-based electrode showed high sensitivity and selectivity in detecting mefenamic acid in cetyltrimethylammonium bromide. The surface morphology of RHG was examined using various techniques, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and atomic force microscopy. The sensor's electrochemical characteristics were analyzed using electrochemical impedance spectroscopy. The RHG/CPE sensor could detect mefenamic acid with a detection limit of 2.13 nM and a linear dynamic range of 1.0 × 10−8 to 4.0 × 10−4 M. The sensor showed negligible interference from co-existing molecules, making it suitable for detecting mefenamic acid in human urine, blood serum, breast milk samples, and pharmaceutical tablets with higher recovery. This study demonstrates the potential of using RHG/CPE sensors in biological, pharmaceutical, or environmental samples to detect mefenamic acid.

Carbon dots-adorned silver nanoparticles as a straightforward sustainable colorimetric sensor for the rapid detection of ketotifen in eye drops and aqueous humor

The rapid and accurate detection of drug molecules in pharmaceutical formulations and biological samples is of paramount importance. In this research article, we present a novel colorimetric sensor based on carbon dots decorated silver nanoparticles (CDs/AgNPs) for the rapid detection of ketotifen (KTF), a widely used antihistamine drug. The CDs were synthesized via a facile one-step microwave-assisted method and subsequently conjugated onto AgNPs through a simple adsorption process, forming a stable CDs/AgNPs composite. The resulting composite exhibited unique optical properties, including a strong absorption peak at 410 nm with remarkable intensity reduction and color changes upon the addition of KTF. The developed colorimetric sensor exhibited a wide linear range of 3.0–40.0 µg mL−1 (R2 = 0.9996), with a %RSD of 2.41, and a low limit of detection (LOD) of 0.981 µg mL−1. Furthermore, the sensor's practical applicability was evaluated by successfully detecting KTF in eye drops and artificial aqueous humor, demonstrating a remarkable percentage recovery exceeding 96.0 %. Finally, a comprehensive evaluation of the greenness and blueness of the method was performed using analytical eco-scale, GAPI, AGREEprep, and BAGI tools. The results of these assessments indicate its exceptional sustainability. Overall, the proposed method holds significant potential for applications in pharmaceutical quality control and therapeutic monitoring, contributing to improved patient care and drug safety in the field of ophthalmology.

Synthesis of cobalt selenide composite material: A novel platform of the electrochemical sensor for sensitive determination of Upadacitinib

This study investigates the first electrochemical determination of Upadacitinib (UPA), a potent Janus kinase (JAK) inhibitor with remarkable efficacy in treating various inflammatory disorders, utilizing a GCE modified with a composite material comprising Co6.8Se8 embedded in porous carbon (Co6.8Se8@NPC). Simultaneously, a novel Co6.8Se8@NPC composite was synthesized using a zeolitic imidazolate framework (ZIF-12) via a one-pot synthesis method. The characterizations confirmed that Co6.8Se8@NPC is uniformly dispersed within the porous carbon network. Leveraging the applications of Metal-Organic Frameworks (MOFs) and their derivatives, Co6.8Se8@NPC was explored for the determination of UPA. The electrochemical behavior of UPA was systematically investigated using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy, upon modifying the GCE with the Co6.8Se8@NPC composite. These materials significantly enhanced sensitivity and selectivity for Upadacitinib detection. Compared with the unmodified electrode, the Co6.8Se8@NPC/GCE exhibited a notable catalytic effect towards the oxidation of UPA, as evidenced by the appearance of an irreversible oxidative peak at a reduced potential and an enhancement in current. The developed method exhibited exceptional performance characteristics with a broad linear range, and low limits of detection and quantification. Moreover, the sensor exhibits good selectivity, repeatability, and stability. Furthermore, the investigation extended to the determination of Upadacitinib in pharmaceutical and biological samples, underscoring the practical applicability of the modified GCE in real-world scenarios.