Current Analytical Chemistry - Online First

Metoclopramide is a widely prescribed antiemetic drug. Its analysis in pharmaceutical formulations often involves procedures using high amounts of toxic chemicals.

A method based on micellar liquid chromatography to determine metoclopramide hydrochloride in several oral dosage forms has been developed.

The drug was resolved from matrix compounds within 6 min using a C18 column with isocratic elution at 1 mL/min utilizing a solution of 0.10 mol/L sodium dodecyl sulfate – 6% 1-pentanol phosphate buffered at pH 7 as mobile phase, and detection by absorbance at 210 nm. Samples were dissolved or diluted in the mobile phase and directly injected; thus, only one solution had to be prepared for the entire procedure. Besides, it contained mainly harmless chemicals and a minimal amount of organic solvent. Results The procedure was validated by the International Council of Harmonization guidelines and the results were: specificity, calibration range (0.5 – 5.0 mg/L), linearity (r² > 0.9990), trueness (98.1 – 100.3%), precision (< 0.7%), robustness, carry-over effect, and system suitability. It was used to analyze commercial samples. Otherwise, it was found the influence of the surfactant on elution strength was nearly three times stronger than that of 1-pentanol.

The procedure was reliable, easy-to-conduct, safe, eco-friendly, short-time, widely available and highly sample-throughput, and then useful for routine analysis of metoclopramide-based dosage forms in pharmaceutical quality control.

Cocrystal engineering of Telmisartan (TEL, a poorly soluble antihypertensive agent) has been undertaken to improve its solubility for the last few years. However, apart from a few handpicked attempts, none of the attempts have been able to improve its solubility by more than 3-5 fold and augment its dissolution by more than 80%.

Addressing these shortcomings, herein, we have designed a novel Telmisartan-maleic acid (TM) cocrystal first by rational modelling with solvent-induced molecular mechanics (SIMM), ab initio based system optimization, descriptor analysis, and finally translating to cocrystals by wet grinding-gradient solvent evaporation method.

Modelling revealed that binary solvent compared to single solvent imparted critical dynamics to seeding the co-crystallite and its structural archipelago. From single solvent to binary solvent, hydrogen bonding to nucleophilic addition of the coformer/s to the central ring revealed a crucial role in assigning the system geometry. The molecular descriptor plot of the generated subsystems (optimized by HF-SCF/def2-SVP method) showed that telmisartan: maleic acid molar ratio <=1:2 under ionizable conditions bear optimum hydrophilicity/hydrophobicity balance. Tonto-guided energy calculation revealed O--H and H--H as the predominant interactions for the crystal packing.

In translational research, our designed TM cocrystal (molar ratio 1:1.5 to 1:2, binary solvent dynamics) exhibited solubility improvement by more than 9 fold in water and showed to release about 92.19% of drugs within 2h (120 min), which superseded the previous reports in this field so far.

This study introduces an innovative two-step approach to fabricate a high-performance Ni2O3/NiO/rGO nanocomposite photocatalyst. The process synergistically combines solvothermal precursor synthesis with calcination and high-energy ultrasonic irradiation, enabling the in-situ formation of a thin Ni2O3 layer on NiO quasi-sphere nanoparticles anchored to a reduced graphene oxide (rGO) matrix.

The incorporation of rGO significantly enhances charge separation, resulting in a dramatic increase in active surface area from 17.1 m²/g to 131 m²/g, and a substantial improvement in the photocatalytic degradation of the resilient Fluorescein dye—achieving an 81% degradation rate under UV light, compared to 36% with pristine NiO.

Comprehensive characterization, including FTIR, XRD, and XPS analyses, confirmed the NiO-Ni2O3 interface transformation, successful reduction of graphene oxide, and critical interactions between NiO and Ni2O3.

This study highlights the promising potential of the Ni2O3/NiO/rGO nanocomposite for environmental remediation, particularly in the degradation of persistent organic pollutants.

Construction and Demolition Waste (CDW) constitutes a major portion of solid waste and presents a significant environmental challenge. This study aims to evaluate the transformation of CDW into a Recycled Aggregate (RA) as a sustainable strategy to mitigate environmental pollution.

The research assesses the mechanical properties and economic benefits of RA concrete, which is made by substituting natural aggregate with RA.

Results indicate that RA has lower density, higher water absorption, and reduced crushing strength compared to natural aggregates. However, RA concrete achieves optimal strength with a 40% replacement rate, marking a critical threshold for material efficiency. An economic analysis confirms the financial viability of using recycled concrete, indicating a favorable investment return. Advances in the research and application of RA suggest its expanding role in engineering applications.

A lifecycle assessment of carbon emissions from concrete production to site transportation was conducted. It revealed that the primary source of emissions in recycled concrete is the raw materials, accounting for about 85% of total emissions. This finding underscores the need to optimize raw material usage to enhance the sustainability of recycled concrete.

Fossil fuels have been used extensively as primary energy sources, which has resulted in nearly depleted reserves, a contaminated environment, and a variety of negative health effects globally. Hydrogen has been proposed by researchers as an effective “carbon neutral” fuel. Large-scale hydrogen production through electrochemical water splitting necessitates the use of inexpensive, extremely effective, and earth-abundant electrocatalysts.

In this study, chitosan–sodium tripolyphosphate (TPP) nanoparticles are combined with CuO nanostructures to produce chitosan–TPP–CuO (CT/CuO) nanocomposite. Chitosan–TPP nanoparticles were first synthesized using the ionic gelation method. These nanoparticles were then extracted, and CuO was synthesized in situ in polymer nanoparticles using a simple chemical precipitation method. Chitosan and CuO are abundantly available and are environmentally beneficial materials. The porous structure and open channels within the chitosan polymer matrix host the CuO nanostructures, which promote electrolyte penetration, mass transport, and charge transfer, while the metal-oxide nanostructures act as catalytic centers. The structural and morphological properties of the CT/CuO nanocomposite were investigated using XRD, HRSEM, and HRTEM. The band gap and functional groups in the material were measured by UV–Vis DRS and FTIR methods, respectively. Elemental analysis was conducted utilizing EDS, HRSEM, and XPS. Thermal characteristics of the CT/CuO nanocomposite were investigated using TG-DTA and DSC methods. Electrochemical techniques were used to investigate the activities of HER and OER.

The XRD examination of the CT/CuO nanocomposite revealed semi-crystalline chitosan peaks and a monoclinic CuO structure. HRSEM and HRTEM pictures indicated that chitosan–TPP nanoparticles and CuO nanostructures were evenly spread and clustered to create a nanoparticulate matrix. UV–Vis DRS indicated that the CT/CuO nanocomposite had a direct band gap of 1.702 eV. The FTIR and XPS studies revealed the various bonds and oxidation states of the nanocomposite. Thermal analyses demonstrated that the inclusion of CuO increased the thermal stability of the CT/CuO nanocomposite. CT/CuO nanocomposite exhibited excellent OER and HER activity, requiring a low overpotential of 444 mV and 379 mV at 10 mA cm⁻² and -10 mA cm⁻², respectively.

Biopolymer metal-oxide nanocomposites could potentially be used as electrocatalysts in water splitting, energy conversion, storage devices, sensors, and several other fields.

In this study, we reported on developing a susceptible, accurate, simple, and economical electrochemical sensor for gabapentin determination in capsules.

The ITO electrode was modified with a layer of Prussian blue nanoparticles and then used as the working electrode. Gabapentin was extracted from commercial capsules, and a series of concentrations of gabapentin were prepared for studying the efficacy of the proposed sensor. The electrochemical measurements were performed using cyclic voltammetry and square wave voltammetry techniques.

The sensitivity and selectivity of the developed electrode toward gabapentin in different interferences, including citric acid, glucose, and urea, were investigated. The modified electrode showed detection and quantification limits of 31.58 and 94.74 nM, respectively, over a dynamic range of concentrations from 100 nM to 3 µM.

The proposed sensor displayed a high sensitivity and selectivity for monitoring gabapentin in pharmaceutical drugs without a noticeable interference. Hence, the modified electrodes are great candidates for gabapentin routine analysis.

Chalcone-type molecules are significant compounds due to their biocompatible properties. This study aimed to examine the electrochemical properties of vanillin chalcone monomer (VC) and its polymer (PANI-VC), as well as to investigate the antioxidant properties of the vanillin chalcone monomer.

VC and PANI-VC were synthesized and characterized using FTIR and UV-Vis spectroscopy. The electrochemical properties of both compounds were investigated using cyclic voltammetry. The antioxidant activity of the monomer was assessed using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay.

Two oxidation peaks and one reduction peak were observed for both the monomer and polymer at pH 3 using cyclic voltammetry in Britton-Robinson buffer solution. The electrochemical oxidation mechanisms of the monomer and polymer were investigated by cyclic voltammetry, and the effects of pH and scan rate were also studied. The electrochemical oxidation mechanism was further evaluated using density functional theory (DFT) computations, revealing that the electrochemical process is adsorption-controlled. The antioxidant activity of VC was assessed using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) method.

Chalcone-type compounds are known for their potential antioxidant, antimicrobial, antifungal, antibacterial, antiviral, antimalarial, and neuroprotective effects. In this study, the electrochemical properties of the synthesized vanillin chalcone monomer and its polymer were examined, and their electrochemical mechanisms were evaluated through DFT calculations. The antioxidant properties of the monomer were compared to those of ascorbic acid using the DPPH method, revealing that the vanillin chalcone monomer possesses significant antioxidant activity.