Degradation Studies Research Articles

Comparative analysis of biopolymer films derived from corn and potato starch with insights into morphological, structural and thermal properties

Starch biopolymer films were prepared using the solvent casting method involving acetic acid hydrolysis and glycerol plasticization. This process facilitated a more uniform distribution of plasticizers within the starch matrix, enhancing the films' flexibility. Fourier-transform infrared (FTIR) and Raman spectroscopy confirmed the formation of ester linkages and structural changes in the biopolymer films, attributed to glycerol integration. The optimal formulation comprised 6% starch, 6.8% acetic acid, and 6.8% glycerol. X-ray diffraction (XRD) analysis revealed a reduction in crystallinity of the starch during film formation, enhancing flexibility. Second harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy indicated that potato starch films had higher crystallinity compared to corn starch films. Thermal analysis via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that potato starch films exhibited lower gelatinization temperatures and higher thermal stability compared to corn starch films. Functional characterization demonstrated that higher starch content decreased water solubility and water vapor transmission rate, while increasing starch content improved the film's structural integrity. The films were hydrophilic, with static water contact angles indicating moderate wettability. Degradation studies showed that the films were stable in neutral and basic conditions but degraded under acidic conditions over time. The results suggest that potato starch films, with optimized glycerol and acetic acid content, offer improved flexibility, thermal stability, and structural integrity compared to corn starch films. Their performance in various conditions highlights their potential for specific applications, particularly where moisture and environmental stability are critical.

Cassava Peel - Cowpea Hull Blended Agro-Waste Fillers: Effect on Mechanical, Morphological and Degradation Properties of Polypropylene

Abstract: This study is aimed at harnessing the effect of cassava peel and cowpea hull blended agro-waste on the mechanical, morphological and degradation properties of polypropylene and recycled polypropylene. Fine powders of mesh size of 75µm cassava peel and cowpea hull were homogeneously mixed at the ratio of 50:50 to form the hybrid filler. The virgin pellets of PP and recycled polypropylene (rPP) were filled with varying weight percentages (5, 10, 15, 20) of the blended filler and the composites produced via injection moulding technique. The mechanical properties; tensile strength, percentage elongation at break, hardness, compressive strength, and shear modulus were studied according to American Society for Testing and Materials (ASTM) standards. The morphological properties were studied with a Scanning Electron Microscope at 10,000 magnifications. The degradation study was achieved by soil burial method for one hundred and eighty (180) days period. The results of the mechanical properties showed increased tensile strength, hardness, compressive strength and shear modulus while the percentage elongation at break decreased as the filler load increases. The micrographs showed that the virgin PP has better adhesion and interfacial bonding with the filler than the rPP. Biodegradation test revealed a reduction in the mass of the composites after one hundred and eighty (180) days burial period indicating that the composite is degradable. From the findings, the cassava peel-cowpea hull blended filler can be used in materials where stiffness and strength is required. Hence, it is suggested that agro-wastes such as cassava peel and cowpea hulls could be used as fillers in production of degradable plastics as they are readily available, cheap and easy to use.

Application of fly ash-TiO2 composites for enhanced adsorption and photocatalytic degradation of fuchsin dye.

It is important to accomplish both photocatalytic efficiency and adsorption capacity in the catalyst to produce a highly effective photocatalyst for complete dye removal from wastewater. In the current investigation, TiO2 and fly ash-TiO2 composites (0.5-5 wt%) were fabricated by sol-gel and wet-impregnation process, and their catalytic performance was evaluated for the effective adsorption and photocatalytic degradation of fuchsin blue dye. The catalysts were characterized by XRD, UV-DRS, SEM, EDS, RAMAN spectroscopy, and N2 adsorption analysis Adsorption and degradation studies were conducted to investigate factors such as pH (2 - 10), adsorbent dose (1-9mg), contact time (30-180min), and initial adsorbate concentration (5-30mg/L) to eradicate fuchsin dye from water. The 5 wt% fly ash-TiO2 catalyst showed a maximum capacity for adsorption of 20.32mg/g and 76% removal of fuchsin dye. The Langmuir isotherm model fitted well to the experimental data, whereas the adsorption process obeyed pseudo-first-order kinetics. When exposed to UV light, a 5 wt% fly ash-TiO2 composite demonstrated maximum photocatalytic degradation of 88% after 180min, followed by a pseudo-first-order kinetic model. The catalyst was easily reusable for five cycles without losing dye removal effectiveness.

Development of a natural rubber latex-based biodevice with mesenchymal stem cells as a potential treatment for skeletal muscle regeneration in gestational diabetes-induced myopathy.

Women with gestational diabetes mellitus show a high risk of developing Gestational Diabetes Induced Myopathy (GDiM). GDiM is characterized by significant pelvic floor skeletal muscle atrophy and urinary incontinence. This study aimed to develop a natural rubber latex (NRL) based biodevice with mesenchymal/stromal stem cells (MSCs) for skeletal muscle regeneration for women with GDiM. NRL showed porosity, roughness, biocompatibility, and bioactivity. MSCs adhesion on the NRL scaffold surface was assessed by scanning electron microscopy (SEM), confocal microscopy, and zymography. The scaffold's physicochemical and biological properties were carried out by Fourier transform infrared spectroscopy (FTIR), swelling and degradation studies, hemolytic activity, and antioxidant activity (AA), using Electronic Paramagnetic Resonance (EPR). MSCs in culture expressed CD90, adhered to plastic, differentiated, and produced fibroblast colonies. A high rate of cell proliferation was seen in MSCs on the NRL scaffold. FTIR analysis confirmed protein structures and polyisoprene in the scaffold. Swelling and degradation showed low water uptake and weight loss. Furthermore, NRL presented a hemolytic rate of 2.90 ± 0.26 % for 24 h, and EPR revealed the scaffold's strong AA. The generated biodevice has potential for muscle regeneration and may be useful as a therapeutic option for skeletal muscle disorders in GDiM or urinary incontinence.

Impact of low temperature exposure on lithium-ion batteries: A multi-scale study of performance degradation, predictive signals and underlying mechanisms

The rapid global expansion of electric vehicles and energy storage industries necessitates understanding lithium-ion battery performance under unconventional conditions, such as low temperature. This study investigates long-term capacity degradation of lithium-ion batteries after low temperature exposure subjected to various C-rate cycles. Findings reveal that low temperature exposure accelerates capacity degradation, especially with increased C-rates or longer exposure durations. A distinctive sunken region appears on the NMC H-stage peak as cycling progresses after low temperature exposure, indicating NMC particle damage and serving as a predictive signal for identifying low temperature exposure batteries. Electrochemical analyses and invasive detection indicate that low temperature exposure causes NMC particle cracking, leading to dead lithium generation. This dead lithium deposits on electrode surfaces, as well as the overconsumption of electrolyte, inhibiting reactions and reducing capacity. Additionally, dead lithium accumulates on separators, impeding ion transport and further accelerating capacity loss. NMC particle cracks develop faster after low temperature exposure due to stress concentration at internal slits. This stress concentration causes the maximum stress within the NMC particles to exceed tensile stress limits, resulting in rapid crack propagation. The internal cracks become larger with prolonged low temperature exposure, causing greater stress concentration and leading to faster crack propagation. Based on these insights, strategies from existing literature are discussed to mitigate the adverse impacts of low temperature exposure on lithium-ion battery performance and enhance the reliability and longevity of lithium-ion battery in extreme conditions.

Design of Experiment and green analytical chemistry principles for developing a robust and sustainable Stability-Indicating HPLC method for Bempedoic acid impurity profiling

Bempedoic acid (BEM), a drug used to lower cholesterol levels in patients with atherosclerosis. Controlling its process-related impurities is crucial due to their potential toxicity. This study details the development of a RP-HPLC method for the analysis of four process-related substances in BEM. To ensure robust chromatographic performance meeting six sigma quality standards, the method was optimized using a combined approach of response surface methodology (specifically, an I-optimal design) and tolerance analysis, integrating predefined specifications for critical method attributes such as resolution, tailing factor, and number of theoretical plates into the developmental process. Chromatographic separation was achieved using a C18 column. The mobile phase consisted of 0.1 % phosphoric acid in water and acetonitrile, utilizing a stepped gradient elution profile. The flow rate was maintained at 0.9 mL/min, with UV detection performed at 210 nm. The column temperature was set to 20 °C. The method demonstrated linearity for BEM process related impurities in the range of LOQ to 30 μg mL−1. The method ability to differentiate the drug substance from its degradation products was confirmed through forced degradation study. The environmental sustainability of the developed method was assessed using multiple Green Analytical Chemistry (GAC) tools. The National Environmental Methods Index (NEMI) showed two green-shaded quadrants, and the Green Certificate modified Eco-scale awarded a score of 70. The Complementary Green Analytical Procedure Index (Complex GAPI) confirmed the method environmentally friendly profile. Additionally, The AGREE tool generated a score of 0.77, indicating strong overall greenness, while the AGREEprep tool, focused on sample preparation, yielded a score of 0.54. Other tools such as the Sample Preparation Metric of Sustainability (SPMS) and the HPLC Environmental Assessment Tool (HPLC-EAT) scored 8.42 and 569, respectively, further demonstrating the method green credentials. This robust and environmentally conscious analytical framework offers significant potential for application in quality control of BEM.

Multifunctional nanocomposites based on kaolinite/titania/iron applied to hydrogen peroxide production and bisphenol–A removal

The rising global demand for hydrogen peroxide, recognized for its eco–friendly properties, underscores the need for greener synthesis methods. Traditional production processes pose environmental risks, while direct synthesis faces challenges like water formation, explosion hazards, and stability issues, limiting industrial application. On the other hand, Bisphenol A (BPA), an endocrine disruptor widely used in plastics, presents significant environmental and health concerns due to its potential leaching into food and water. The present work introduces efficient and selective photocatalysts aimed at sustainable hydrogen peroxide synthesis and BPA degradation. Both processes were enhanced by the synergistic properties of Fe2O3–TiO2 nanoparticles dispersed within a kaolinite matrix. The Fe2O3–TiO2 photocatalysts, characterized by photoluminescence spectroscopy and X–ray diffraction, showed reduced emission upon iron incorporation and anatase presence on the kaolinite surface. The photocatalytic activity was evaluated through hydroxylation of terephthalic acid, revealing a 127 μmol/L min hydroxylation rate for the KaFeTi400 sample. BPA degradation studies indicated optimal performance in acidic conditions, achieving 96 % removal in 2 h and 98 % in 4 h, with the addition of H2O2 enhancing efficiency. Further, the photocatalyst facilitated benzyl alcohol oxidation to benzaldehyde, demonstrating a H2O2 production rate of 120 μmol. These findings highlight the multifunctional capabilities and environmental benefits of the photocatalyst, underscoring its potential for sustainable hydrogen peroxide synthesis and broader applications in environmental remediation. The catalysts address the pressing challenges associated with hydrogen peroxide synthesis and pollutant removal, particularly in the context of sustainability and environmental impact.

Green RP-HPLC method for simultaneous quantification of epigallocatechin-3-gallate and rosmarinic acid in lipid-based nanocarriers and biological fluids: Quality by Design-driven optimization and lean six sigma approach

This study presents the development and validation of a reverse-phase high-performance liquid chromatography (RP-HPLC) method for concurrent quantification of EGCG and RA in prepared lipid-based nanocarriers and biological fluids using a QbD approach, greenness assessment, and Six-Sigma methodology. Initially, variations in critical analytical attributes were identified using the Ishikawa fishbone diagram and Risk Priority Number scores. A Taguchi Orthogonal Array design was employed to screen the critical method parameters influencing method development. Systematic optimization of the RP-HPLC method was subsequently achieved using a Box-Behnken design, with the % organic phase, flow rate, and column temperature as the variables. The responses were retention time, tailing factor, and theoretical plates for both EGCG and RA. Chromatographic separation was accomplished with a methanol and 0.1% formic acid (60:40) isocratic flow system on a Phenomenex Luna C18 column (4.6 × 250 mm, 5 μm) at a 1 mL/min flow rate. The method was rigorously validated according to ICH guidelines. Linearity was observed over a concentration range of 2 to 10 µg/mL for both EGCG and RA, yielding correlation coefficients of 0.998 and 0.999, respectively. The LOD and LOQ were determined to be 0.51 µg/mL and 1.54 µg/mL for EGCG, and 0.35 µg/mL and 1.07 µg/mL for RA. Moreover, the %RSD for all validation parameters were consistently below 2%. Forced degradation studies were conducted under acidic, basic, oxidative, and photolytic conditions to elucidate potential degradation pathways and identify degradation products. The developed method was applied to estimate EGCG and RA in prepared lipid-based nanocarriers and biological fluids like blood plasma and urine. Recovery assays in lipid-based nanocarriers, plasma, and urine samples demonstrated excellent recoveries (96.2–102.1%). The method's greenness was assessed using various tools, and its accuracy was evaluated using Six Sigma methodology. Overall, the developed HPLC method offers a rapid, sensitive, and reliable approach for quantifying EGCG and RA, laying the groundwork for their further investigation as anticancer agents, alone and in combination therapies.

Microstructure degradation and creep failure study of the dissimilar metal welded joint of heat-resistant steel and Inconel 617 alloy tested at 650 °C and applied stress range of 100–150 MPa

The advanced ultra-supercritical (A-USC) power plant system is anticipated to become India's next-generation base-load power station. To adopt AUSC technology, dissimilar welded joints (DWJs) between heat-resistant steels and the nickel-based alloys, using the nickel-based fillers, will need to be implemented. However, failure of dissimilar welded joints from P92 steel base metal or the heat affected zone (HAZ) has been commonly observed under high-temperature creep conditions. In the present study, the creep rupture behaviours and rupture mechanisms of DWJ between the Ni-based alloy Inconel 617 and heat-resistant P92 steel with Inconel 617 (ERNiCrCoMo-1) filler metal were investigated. Creep tests were conducted at 650 °C in the stress range of 100–150 MPa. To examine the creep rupture behaviour of the DWJ samples, optical microscopy (OM), scanning electron microscopy (SEM) and microhardness tests were performed. Cross-sectional images of the fractured creep specimens tested under various operating conditions revealed failures originating from distinct locations, including the P92 base metal and the inter-critical heat affected zone (HAZ). The specimen tested at 650 °C/150 MPa exhibited failure originating from the P92 base metal, whereas the specimen tested at 650 °C under the stress range of 100–130 MPa showed failure from the inter-critical heat affected zone (ICHAZ). The failure from P92 BM was primarily governed by plastic deformation, with the growth and coalescence of dimples ultimately resulting in trans-granular fracture. The specimens tested at 650 °C/100–130 MPa, which failed from the ICHAZ, exhibited a typical Type IV inter-granular failure. This failure mode is primarily attributed to matrix softening in HAZ, weakening of the boundaries, coarsening of the precipitates, and the evolution of intermetallic Laves phases. The specimen that failed in the stress range of 100–130 MPa exhibited a high density of microvoids in the ICHAZ, along with a few microvoids in the FGHAZ. The weld metal showed negligible degradation in microstructure, while the hardness study revealed a significant increase in hardness with an increase in rupture time, i.e., a decrease in applied stress and it was attributed to evolution of the new carbide phases in weld metal. Coarsening of the carbide precipitates was observed in each zone of the HAZ of P92 steel as well as in the base metal. The EDS study of the fracture tip and the FGHAZ/ICHAZ of the specimen that failed under stresses of 100 MPa and 120 MPa confirmed the evolution of intermetallic Laves phases. High magnification SEM images confirmed that triple boundaries are preferential locations for microvoid nucleation. The failed specimen showed the presence of microvoids near the carbide precipitates, with a large density of both coarse and fine precipitates confirmed all around and inside the microvoids. The ICHAZ and FGHAZ confirmed the formation of fine prior austenite grain boundaries (PAGBs) during the welding thermal cycle, which exhibited a lower density of carbide precipitates and this played a major role in Type IV failure.

Sustainable Photodegradation of Amoxicillin in Wastewater with a Nickel Aluminate and ZnO Heterosystem Oxides: Experimental and Gaussian Process Regression Modeling Studies

The wastewater generated by the pharmaceutical industry poses a risk to the environment due to undesirable characteristics such as low biodegradability, high levels of contaminants, and the presence of suspended solids, in addition to the high load of organic matter due to the presence of drugs and other emerging products in the effluent. This study aims to reduce the impact of wastewater pollution by removing amoxicillin (AMO) antibiotics as an organic pollutant. In this concept, two synthesized catalysts, NiAl2O4 and ZnO, are sensitive oxides to light energy. The prepared materials were then characterized using X-ray diffraction, UV–vis solid reflectance diffuse, Raman spectroscopy, scanning electron microscopy, BET, and ATR-FTIR spectroscopy. The effects of principal operating parameters under sunlight, namely, the percentage of the mixture of NiAl2O4 and ZnO, the pH of the medium, and the initial concentration of the antibiotic were studied experimentally to determine the optimal conditions for achieving a high degradation rate. The results showed that photodegradation is higher at a pH of 6, with a weight percentage of the mixture of 50% for both catalysts in 1 g/L of the total catalyst dose. Then, the effect of the initial concentration of AMO on the photodegradation reaction showed an important influence on the photodegradation process; as the degradation rate decreases, the initial AMO concentration increases. A high degradation rate of 92% was obtained for an initial AMO concentration of 10 mg/L and a pH of 6. The kinetic study of degradation established that the first-order model and the Langmuir–Hinshelwood (LH) mechanism fit the experimental data perfectly. The study showed the success of using heterosystem photocatalysts and sustainable energy for effective pharmaceutical removal, which can be extended to treat wastewater with other organic emerging pollutants. On the other hand, modeling was introduced using Gaussian process regression (GPR) to predict the degradation rate of AMO under sunlight in the presence of heterogeneous ZnO and NiAl2O4 systems. The model evaluation criteria of GPR in terms of statistical coefficients and errors show very interesting results and the performance of the model used. Where statistical coefficients were close to one (R = 0.9981), statistical errors were very small (RMSE = 0.1943 and MAE = 0.0518). The results suggest that the model has a strong predictive power and can be used to optimize the process of AMO removal from wastewater.

Photochemical and Sono-Photochemical Studies of Zn (II) Porphyrin-conjugated Chitosan Hydrogels for Enhanced Singlet Oxygen Generation

This study explores the synthesis, characterization, photochemical, and sono-photochemical properties of covalently conjugated porphyrin-chitosan hydrogels for potential application in photodynamic therapy (PDT) and sono-photodynamic therapy (SPDT). The efficient production of singlet oxygen, a crucial reactive oxygen species (ROS) in these therapies, was investigated. Zinc(II) porphyrins 1 and 2 were synthesized by metal insertion to free based porphyrins and covalently linked to chitosan via Schiff-base reaction to produce chitosan hydrogel CS-1 and CS-2 (conjugation via phenylacetylene spacer). The synthesized compounds were characterized using standard spectroscopic techniques, confirming successful conjugation. Scanning electron microscopy (SEM) analysis demonstrating the homogeneous distribution of porphyrins within the hydrogel matrix. Photophysical and photochemical properties, including ground state absorption and singlet oxygen generation, were evaluated for both porphyrin complexes and chitosan-conjugated hydrogels in DMSO. The porphyrin-hydrogel structures showed superior singlet oxygen generation efficiency. Sono-photochemical studies showed further enhanced singlet oxygen generation, with the highest quantum yield (ΦΔ= 0.81) observed for the chitosan hydrogel CS-2. The results demonstrated enhanced singlet oxygen generation in the hydrogel structures, particularly under simultaneous ultrasound and light irradiation, indicating their potential efficacy in PDT and SPDT applications. Additionally, photo degradation studies revealed the stability of the synthesized compounds under light irradiation. These findings highlight the potential of porphyrin-conjugated chitosan hydrogels as effective photosensitizers for PDT and SPDT applications.

Functional profiling of the rhizospheric Exiguobacterium sp. for dimethoate degradation, PGPR activity, biofilm development, and ecotoxicological risk

This study introduces an indigenous bacterial strain, Exiguobacterium sp. (L.O), isolated from sugarcane fields in Sevur, Tamil Nadu, which has adapted to prolonged exposure to dimethoate. The strain demonstrated the capability to utilize 150 ppm of dimethoate as its sole carbon source, achieving a remarkable degradation rate of 95.87% within 5 days in mineral salt media. Gas chromatography–mass spectrometry (GC–MS) analyses identified the presence of intermediate by-products formed during degradation, like methyl diethanol amine and aspartyl glycine ethyl ester. Notably, phosphorothioic O, O, S-acid, an expected end product in the degradation of dimethoate, was also identified, further confirming the strain’s effective metabolic breakdown of the pesticide. Further degradation study and analysis of changes in functional group was performed by FTIR, and a hypothetical degradation pathway was elucidated showing the course of dimethoate metabolism by the strain. Exiguobacterium sp. (L.O) also displayed significant plant growth-promoting traits, including the production of HCN, IAA, and ammonia and the formation of biofilms, which enhance its utility in agricultural applications. The ecotoxicity study revealed the degradation by-products exhibited reduced toxicity compared to the parent compound dimethoate, highlighting the strain’s potential not only for bioremediation but also for supporting sustainable agricultural practices. This research presents a novel application of Exiguobacterium sp. (L.O), integrating the bioremediation of the organophosphate pesticide dimethoate with agricultural enhancement. This approach is critical for addressing the challenges associated with pesticide pollution in agricultural practices. This study is likely the first to demonstrate the application of this strain in the degradation of dimethoate, as suggested by an extensive review of the literature.

Integrative greenness, blueness and whiteness determination of analytical RP-HPLC method for identifying Imipenem, Cilastatin and Relebactam in combined tablet form followed by forced degradation studies

Most clinically preferred, US FDA and EU approved anti-infective drug, a multi-component formulation of Imipenem (IPM), Cilastatin (CS) and Relebactum (REL). The combination is used in medicating the most complicated, gram-negative bacterial infections. Henceforth, it requires the development of selective, precise, accurate, robust analytical method. Hence the present work comprises RP-HPLC method development for determination of IPM, CS and REL. The detection is achieved by using new and apt conditions i.e., Discovery C18 (4.6 × 150 mm, 5 µm) column, 0.01 N Potassium Dihydrogen Phosphate buffer: Acetonitrile (60:40) as mobile phase. The detection was found at short RT i.e., 2.32, 3.08, and 3.62-min for IPM, CS and REL correspondingly. Good sensitivity was observed, where LOD of 0.11 µg/ml (IPM), 0.14 µg/ml (CS), and 0.06 µg/ml (REL) was obtained. While, LOQ was noticed at 0.33 µg/ml (IPM), 0.43 µg/ml (CS) and 0.18 µg/ml (REL). As a counterpart, other study of forced degradation was also performed for the selected drugs at different extreme conditions. A sustainability evaluation has been done on the proposed method. The creative tools such as AGREE, GAPI, ChlorTox scale in green analytical counterpart were performed providing good score. Another BAGI software was opted as blue principle-evaluator, that resulted in a good score of 85 %. Highlighting the use of the most recent sustainability determination software, RGBfast model in present work with a good score of 74 %. Moreover, white and green evaluation has been performed in the form of comparative mode, for better understanding of the significance of current method.

CMC/Gel/GO 3D-printed cardiac patches: GO and CMC improve flexibility and promote H9C2 cell proliferation, while EDC/NHS enhances stability

In this research, carboxymethyl cellulose (CMC)/gelatin (Gel)/graphene oxide (GO)-based scaffolds were produced by using extrusion-based 3D printing for cardiac tissue regeneration. Rheological studies were conducted to evaluate the printability of CMC/Gel/GO inks, which revealed that CMC increased viscosity and enhanced printability. The 3D-printed cardiac patches were crosslinked with N-(3-dimethylaminopropyl)-n'-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) (100:20 mM, 50:10 mM, 25:5 mM) and then characterized by mechanical analysis, electrical conductivity testing, contact angle measurements and degradation studies. Subsequently, cell culture studies were conducted to evaluate the viability of H9C2 cardiomyoblast cells by using the Alamar Blue assay and fluorescence imaging. A high concentration of EDC/NHS (100:20 mM) led to the stability of the patches; however, it drastically reduced the flexibility of the scaffolds. Conversely, a concentration of 25:5 mM resulted in flexible but unstable scaffolds in phosphate buffer saline solution. The suitable EDC/NHS concentration was found to be 50:10 mM, as it produced flexible, stable, and stiff cardiac scaffolds with high ultimate tensile strength. Mechanical characterization revealed that % strain at break of C15/G7.5/GO1 exhibited a remarkable increase of 61.03% compared to C15/G7.5 samples. The improvement of flexibility was attributed to the hydrogen bonding between CMC, Gel and GO. The electrical conductivity of 3D printed CMC/Gel/GO cardiac patches was 7.0 × 10-3S cm-1, demonstrating suitability for mimicking the desired electrical conductivity of human myocardium. The incorporation of 1 wt% of GO and addition of CMC concentration from 7.5 wt% to 15 wt% significantly enhanced relative % cell viability. Overall, although this research is at its infancy, CMC/Gel/GO cardiac patches have potential to improve the physiological function of cardiac tissue.

Acid Degradation Study of Dapagliflozin: Structural Characterization of Dapagliflozin and its Degradation Products Using Advanced Analytical Techniques and In Silico Toxicity Prediction

ABSTRACTThe research investigates the stress degradation behavior of Dapagliflozin (DAP), a type‐2 diabetic treatment, following International Council for Harmonization Guidelines. It found that DAP is stable in thermal, photolytic, neutral, and alkaline hydrolysis conditions, but significant degradation was detected in acid hydrolysis. Two novel degradation products (DPs) were identified and isolated in acid degradation, providing the first documented structural characterization of all two DPs. The identification of DPs was achieved through the use of ultra‐high‐performance liquid chromatography–mass spectrometry, semi‐preparative high‐performance liquid chromatography, and nuclear magnetic resonance spectroscopy for structural characterization. In acid degradation, a total of two primary DPs, degradation products 1 and 2 (DP1 and DP2), were found and separated. It was not previously reported that the two DPs that were generated were all new. This is the first time that these two DPs’ full structural characterizations employing cutting‐edge analytical techniques have been recorded. In the current work, liquid chromatography mass spectroscopy and nuclear magnetic resonance spectroscopy were employed to get a specific confirmation of DP structures. In the further, degrading impurity with lower runtime will also be identified using the current method.

Concurrent estimation of Pregabalin and Etoricoxib by new stability indicating RP-UPLC approach: application in assay of commercial tablets

The present research aims to establish new stability indicating RP-UPLC method for concurrently estimating Pregabalin and Etoricoxib in blended powder and their combined tablet formulation. The effective separation of Pregabalin and Etoricoxib achieved with HSS column C18 (150 × 2.1 mm, 1.8 µm), 0.1% orthophosphoric acid: acetonitrile in 65:35 v/v) at a flow rate of 0.3 mL/min, and isocratic elution at 228 nm. The elution of PRB and ETB was noticed at 1.56 and 2.01 min, with good resolution and system suitability with the developed approach. PRB and ETB have shown linear responses from 18.75 to 112.5 µg/mL and 15 to 90 µg/mL, respectively. The range of the % RSD for intraday and inter-day precision was 0.33 to 0.81. The LOD and LOQ of Pregabalin and Etoricoxib were computed to be 0.07 µg/mL, 0.21 µg/mL, and 0.01 µg/mL, 0.04 µg/mL, respectively, by standard deviation method. The validation method was carried out using ICH standards. The stability- indicating the feature of the method was confirmed by the forced degradation studies where degradants generated by stress testing were clearly distinguished from the peaks of analytes. The shorter elution period and superior sensitivity of both analytes with this method are appropriate for regular analysis of Pregabalin and Etoricoxib.Graphical

Experimental and Theoretical Study of the OH-Initiated Degradation of Ethylenediamine (NH2CH2CH2NH2) under Simulated Atmospheric Conditions. Part 1: Kinetics of the Ethylenediamine + OH Gas Phase Reaction

Experimental and Theoretical Study of the OH-Initiated Degradation of Ethylenediamine (NH₂CH₂CH₂NH₂) under Simulated Atmospheric Conditions. Part 1: Kinetics of the Ethylenediamine + OH Gas Phase Reaction

Stability‐Indicating RP‐HPLC Method for Lopinavir Estimation in Pharmaceutical Co‐Crystals: A Design of Expert Approach

ABSTRACTThe primary objective of this investigation was to develop and validate a robust reversed‐phase high‐performance liquid chromatography (RP‐HPLC) method for the quantification of lopinavir in co‐crystals formed with fumaric acid and acetamide. A Box–Behnken design within the design of the experiment framework was employed to optimize chromatographic conditions. The method utilized a Phenomenex Luna C18 column and a mobile phase of methanol and 0.1% formic acid (80:20 v/v) at a flow rate of 1 mL/min, with detection at 259 nm. Validation followed ICH Q2 (R1 and R2) guidelines, confirming the method's specificity, accuracy, precision, linearity, and robustness. Co‐crystals of lopinavir were prepared using liquid‐assisted grinding and reaction crystallization techniques. The validated HPLC method successfully quantified lopinavir in these co‐crystals, with recovery rates ranging from 96.3% to 99.8%. Forced degradation studies under various stress conditions (acidic, base, oxidative, thermal, and photolytic) demonstrated the method's capability to distinguish lopinavir from its degradation products. In conclusion, the developed RP‐HPLC method is suitable for routine analysis and quality control of lopinavir in co‐crystal formulations. This method not only provides precise quantification but also offers insights into the enhanced delivery potential of lopinavir through co‐crystallization, contributing to improved therapeutic efficacy in HIV/AIDS treatment.

Evaluation of Ruthenium Oxide Nanoparticles as Photocatalysts: Efficiency in Organic Dye Degradation and Environmental Impact Studies

ABSTRACTOne of the most promising nanoscale materials for photodegradation is ruthenium oxide nanoparticles, which are abbreviated as RuO2 nanoparticles. Ruthenium oxide nanoparticles (RuO2 NPs) are promising nanomaterials for photodegradation. Several research methods have examined their size, phase study, and shape. We also examined RuO2 nanoparticle photocatalysis in rhodamine‐B (RhB) and acridine orange (AO) dyes degradation. We discovered that these nanoparticles were highly photocatalytic when exposed to UV light. This non‐toxic method uses no solvents. Analyzing synthesized RuO2 nanoparticles required FESEM, XRD, XPS (x‐ray photoelectron spectroscopy), FTIR (Fourier transform infrared), and UV‐visible spectroscopy. The newly synthesized nanoparticles were evaluated for catalytic activity by degrading RhB and AO dyes. After the first‐order reaction, kinetics determined the photocatalytic efficiency against RhB and AO dyes, which degraded at 84% and 82%, respectively. A tamarind plant study found no phytotoxicity in treated effluents. RuO2 catalysts degrade organic dyes in industrial wastewater efficiently and inexpensively. The study shows RuO2 nanoparticles as very effective photocatalysts for degrading organic dyes, exhibiting better performance than conventional materials. In addition, it assesses the phytotoxicity of RuO2 nanoparticles, offering valuable information about their environmental consequences and safety for prospective widespread application.

AQbD-enhanced green RP-UPLC-PDA methodology for quantification and forced degradation studies for omeprazole, amoxicillin, and rifabutin

The ternary combination like omeprazole (OMP), amoxicillin (AMX), and rifabutin (RFB) was approved by the FDA in November 2019 for combating Helicobacter pylori infections and ulcers caused by this infection. This study aims to develop and authenticate a robust and eco-friendly RP-UPLC technique aimed at the concurrent analysis of OMP, AMX, and RFB, following ICH guidelines, Analytical Quality by Design (AQbD), and green analytical chemistry (GAC) principles. The analysis used the Thermo C18 column (100 mm × 2.1 mm, 1.7 µm), ethanol, and formic acid solution (43:57) as mobile phase with a flow rate of 0.2 ml/min at 272 nm. The method was developed based on the ICH Q14 and validated according to ICH Q2(R1) followed by Forced degradation studies under various conditions. The method showed good linearity for OMP, AMX, and RFB, with coefficient of determination (r2) of 0.9995, 0.9993, and 0.9997, respectively. Precision studies indicated low %RSD values, confirming high reproducibility. Forced degradation studies confirmed the stability of the drugs for 30 min in acid, base, and redox reactions, and they were also stable for 6 h at 105 °C in dry conditions. GAPI assessment depicted a green and yellow pictogram, AGREE scored 0.85, BAGI scored 80, and RGB12 Whiteness Assessment Tool scored 97.5%. The developed RP-UPLC-PDA technique is robust and reliable for the concurrent quantification of the triple combination. It aligns with sustainability goals, enhancing the efficiency and environmental sustainability of pharmaceutical analysis, and setting a benchmark for future analytical methods.