Isoquinoline-based intrinsic fluorescence assessment of erythropoiesis-stimulating agent, Roxadustat (FG-4592), in tablets: applications to content uniformity and human plasma evaluation.

In the present study, a first validated and green spectrofluorimetric approach for its assessment and evaluation in different matrices was investigated. After using an excitation wavelength of 345 nm, Roxadustat (ROX) demonstrates a highly native fluorescence at an emission of 410 nm. The influences of experimental factors such as pH, diluting solvents, and different organized media were tested, and the most appropriate solvent choice was ethanol. It was confirmed that there was a linear relationship between the concentration of ROX and the relative fluorescence intensity in the range 60.0-1000.0 ng ml-1, with the limit of detection and limit of quantitation, respectively, being 17.0 and 53.0 ng ml-1. The mean recoveries % [±standard deviation (SD), n = 5] for pharmaceutical preparations were 100.11% ± 2.24%, whereas for plasma samples, they were 100.08 ± 1.08% (±SD, n = 5). The results obtained after the application of four greenness criteria, Analytical Eco-Scale metric, NEMI, GAPI, and AGREE metric, confirmed its eco-friendliness. In addition, the whiteness meter (RGB12) confirmed its level of sustainability. The International Council for Harmonisation (ICH) criteria were used to verify the developed method through the study in both spiked plasma samples and content uniformity evaluation. An appropriate standard for various applications in industry and quality control laboratories was developed.

Do Ionic Liquids Exhibit the Required Characteristics to Dissolve, Extract, Stabilize, and Purify Proteins? Past-Present-Future Assessment.

Proteins are highly labile molecules, thus requiring the presence of appropriate solvents and excipients in their liquid milieu to keep their stability and biological activity. In this field, ionic liquids (ILs) have gained momentum in the past years, with a relevant number of works reporting their successful use to dissolve, stabilize, extract, and purify proteins. Different approaches in protein-IL systems have been reported, namely, proteins dissolved in (i) neat ILs, (ii) ILs as co-solvents, (iii) ILs as adjuvants, (iv) ILs as surfactants, (v) ILs as phase-forming components of aqueous biphasic systems, and (vi) IL-polymer-protein/peptide conjugates. Herein, we critically analyze the works published to date and provide a comprehensive understanding of the IL-protein interactions affecting the stability, conformational alteration, unfolding, misfolding, and refolding of proteins while providing directions for future studies in view of imminent applications. Overall, it has been found that the stability or purification of proteins by ILs is bispecific and depends on the structure of both the IL and the protein. The most promising IL-protein systems are identified, which is valuable when foreseeing market applications of ILs, e.g., in "protein packaging" and "detergent applications". Future directions and other possibilities of IL-protein systems in light-harvesting and biotechnology/biomedical applications are discussed.

Efficient Sampling of Cavity Hydration in Proteins with Nonequilibrium Grand Canonical Monte Carlo and Polarizable Force Fields.

Prediction of the hydration levels of protein cavities and active sites is important to both mechanistic analysis and ligand design. Due to the unique microscopic environment of these buried water molecules, a polarizable model is expected to be crucial for an accurate treatment of protein internal hydration in simulations. Here we adapt a nonequilibrium candidate Monte Carlo approach for conducting grand canonical Monte Carlo simulations with the Drude polarizable force field. The GPU implementation enables the efficient sampling of internal cavity hydration levels in biomolecular systems. We also develop an enhanced sampling approach referred to as B-walking, which satisfies detailed balance and readily combines with grand canonical integration to efficiently calculate quantitative binding free energies of water to protein cavities. Applications of these developments are illustrated in a solvent box and the polar ligand binding site in trypsin. Our simulation results show that including electronic polarization leads to a modest but clear improvement in the description of water position and occupancy compared to the crystal structure. The B-walking approach enhances the range of water sampling in different chemical potential windows and thus improves the accuracy of water binding free energy calculations.

Subcritical Water Extraction to Valorize Grape Biomass-A Step Closer to Circular Economy.

With the increase in the world population, the overexploitation of the planet's natural resources is becoming a worldwide concern. Changes in the way humankind thinks about production and consumption must be undertaken to protect our planet and our way of living. For this change to occur, sustainable development together with a circular economic approach and responsible consumption are key points. Agriculture activities are responsible for more than 10% of the greenhouse gas emissions; moreover, by 2050, it is expected that food production will increase by 60%. The valorization of food waste is therefore of high importance to decrease the environmental footprint of agricultural activities. Fruits and vegetables are wildly consumed worldwide, and grapes are one of the main producers of greenhouse gases. Grape biomass is rich in bioactive compounds that can be used for the food, pharmaceutical and cosmetic industries, and their extraction from this food residue has been the target of several studies. Among the extraction techniques used for the recovery of bioactive compounds from food waste, subcritical water extraction (SWE) has been the least explored. SWE has several advantages over other extraction techniques such as microwave and ultrasound extraction, allowing high yields with the use of only water as the solvent. Therefore, it can be considered a green extraction method following two of the principles of green chemistry: the use of less hazardous synthesis (principle number 3) and the use of safer solvents and auxiliaries (principle number 5). In addition, two of the green extraction principles for natural products are also followed: the use of alternative solvents or water (principle number 2) and the use of a reduced, robust, controlled and safe unit operation (principle number 5). This review is an overview of the extraction process using the SWE of grape biomass in a perspective of the circular economy through valorization of the bioactive compounds extracted. Future perspectives applied to the SWE are also discussed, as well as its ability to be a green extraction technique.

Ultrasound assisted membrane-assisted solvent extraction for the simultaneous assessment of some drugs involved in drug-facilitated sexual assaults by liquid chromatography-tandem mass spectrometry.

A simple and highly efficient ultrasound assisted membrane-assisted solvent extraction (MASE) pre-treatment method for urine has been developed and validated for the simultaneous determination of twenty-two drugs involved in drug-facilitated sexual assaults (DFSAs) by liquid chromatography-tandem mass spectrometry. MASE was performed with 4.0 mL of urine (pH adjusted at 12), 400 µL of hexane as an organic solvent inside the polypropylene membrane, and ultrasonication (45 kHz, 120 W) for 10 min. A pre-concentration factor of 40 was achieved after evaporation (N2 stream) and re-dissolution in 100 µL of methanol. Analytes were separated using a Zorbax Eclipse Plus C18 column under gradient elution with aqueous 10 mM NH4HCO3 (pH 8.0) and methanol as mobile phases. Matrix-matched calibrations allowed the assessment of DFSA drugs of quite different octanol-water partition coefficients (Ko/w), from 1.32 101 for pregabalin to 2.45 105 for clomipramine (Log P values from 1.12 (pregabalin) to 5.39 (clomipramine)). The limit of detection (LOD) was between 0.0075 to 0.37 µg L-1, with analytical recoveries ranging from 73 to 103%, and relative standard deviations (RSDs) within the 2-20% range. The applicability of the method was demonstrated after analysing urine samples under forensic investigation.

Continuous Synthesis of Cinnarizine Salt with Malic Acid by Applying Green Chemistry Using Water-Assisted Twin Screw Extrusion.

Organic solvent-free process or green chemistry is needed for manufacturing pharmaceutical salts to avoid various environmental, safety, and manufacturing cost issues involved. In this study, a cinnarizine (CNZ) salt with malic acid at a 1:1 molar ratio was successfully prepared by twin screw extrusion (TSE) with water assistance. The feasibility of salt formation was first evaluated by screening several carboxylic acids by neat grinding (NG) and liquid-assisted grinding (LAG) using a mortar and pestle, which indicated that malic acid and succinic acid could form salts with CNZ. Further studies on salt formation were conducted using malic acid. The examination by hot-stage microscopy revealed that the addition of water could facilitate the formation and crystallization of CNZ-malic acid salt even though CNZ is poorly water-soluble. The feasibility of salt formation was confirmed by determining the pH-solubility relationship between CNZ and malic acid, where a pHmax of 2.7 and a salt solubility of 2.47 mg/mL were observed. Authentic salt crystals were prepared by solution crystallization from organic solvents for examining crystal properties and structure by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, solid-state 13C and 15N nuclear magnetic resonance (NMR), and single-crystal X-ray diffraction (SXD). These techniques also established that a salt, and not a cocrystal, was indeed formed. The CNZ salt crystals were then prepared by TSE of a 1:1 CNZ-malic acid mixture, where the addition of small amounts of water resulted in a complete conversion of the mixture into the salt form. The salts prepared by solvent crystallization and water-assisted TSE had identical properties, and their moisture sorption profiles were also similar, indicating that TSE is a viable method for salt preparation by green chemistry. Since TSE can be conducted in a continuous manner, the results of the present investigation, if combined with other continuous processes, suggest the possibility of continuous manufacturing of drug products from the synthesis of active pharmaceutical ingredients (APIs) to the production of final dosage forms.

Determination of Flavonoid Compounds in Shanxi Aged Vinegars Based on Hydrophobic Deep Eutectic Solvent VALLME-HPLC Method: Assessment of the Environmental Impact of the Developed Method.

This research presents a novel, eco-friendly, vortex-assisted liquid-liquid microextraction (VALLME) approach, integrating hydrophobic deep eutectic solvents (DESs) with HPLC for the identification and quantification of nine specific flavonoids in Shanxi aged vinegar (SAV). The parameters of DES-VALLME, including the ratio of trioctylmethylammonium chloride to 1,4-butanediol (1:6), DES volume (150 µL), vortex duration (5 min), the concentration of NaCl (0.40 g), and centrifugation time (10 min), were optimized to achieve the maximum extraction efficiency of target substances. Under these optimal conditions, quantitative analyses performed via HPLC demonstrated a broad linear range of 0.20-50.00 µg/mL and correlation coefficients (r2) greater than 0.9944 for all nine calibration curves. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.09-0.18 µg/mL and 0.30-0.60 µg/mL, respectively, ensuring high sensitivity. The relative standard deviations for intra-day and inter-day variability were within the acceptable range, 2.34-3.77% and 3.04-4.96%, respectively, demonstrating the method's reliability. The recovery rates ranged from 85.97% to 108.11%, underscoring the method's precision. This technique exhibited a significant enrichment effect (enrichment factor: 43 to 296) on SAV flavonoids. Notably, the eco-friendliness of this procedure was evaluated using the Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric. The results suggested that this technique is a viable green alternative to traditional flavonoid determination methods in SAV. In summary, this novel method provides a theoretical basis for assessing flavonoid content in SAV samples and tracing SAV products. This contribution has significant implications for enhancing analytical techniques in food chemistry and environmental science and the sustainable development of the food industry.

Assessment of endocrine disruptor pollutants and their metabolites in environmental water samples using a sustainable natural deep eutectic solvent-based analytical methodology.

In this work, an evaluation of the occurrence of fifteen phthalates, four metabolites and one adipate in different groundwater, seawater and wastewater samples has been carried out due to their relevance on human health as they act as endocrine disruptors. For this purpose, a sustainable, fast and easy-handling vortex-assisted liquid-liquid microextraction method using a natural hydrophobic deep eutectic solvent based on menthol and carvacrol as extraction agent, combined with ultra-high performance liquid chromatography-mass spectrometry technique, has been developed and applied for the first time. An optimization was performed to evaluate four important factors affecting the extraction performance, and an analytical validation was carried out in terms of matrix effect, linearity, extraction efficiency, and sensitivity. Recovery values were obtained in the range 72-119% for all analytes (except for monoethyl phthalate: 61.1-72.3%) with relative standard deviation values lower than 17%. Limits of quantification were found between 0.91 and 8.09 µg L-1. As a result of the assessment of 31 different environmental water samples, monoethyl phthalate, diethyl phthalate, dibutyl phthalate and bis (2-ethylhexyl) phthalate were detected and quantified at different concentrations in the range 2.59-21.17 µg L-1 in 6 samples, and diallyl phthalate, butyl benzyl phthalate, dipentyl phthalate, dicyclohexyl phthalate, dihexyl phthalate and bis (2-ethylhexyl) adipate were detected in 20 more, showing the exposition of the population to these hazardous substances.

Critical Assessment of Self-Consistency Checks in the All-Atom Molecular Dynamics Simulation of Intrinsically Disordered Proteins.

All atom simulations can be used to quantify conformational properties of Intrinsically Disordered Proteins (IDP). However, simulations must satisfy convergence checks to ensure observables computed from simulation are reliable and reproducible. While absolute convergence is purely a theoretical concept requiring infinitely long simulation, a more practical, yet rigorous, approach is to impose Self Consistency Checks (SCCs) to gain confidence in the simulated data. Currently there is no study of SCCs in IDPs, unlike their folded counterparts. In this paper, we introduce different criteria for self-consistency checks for IDPs. Next, we impose these SCCs to critically assess the performance of different simulation protocols using the N terminal domain of HIV Integrase and the linker region of SARS-CoV-2 Nucleoprotein as two model IDPs. All simulation protocols begin with all-atom implicit solvent Monte Carlo (MC) simulation and subsequent clustering of MC generated conformations to create the representative structures of the IDPs. These representative structures serve as the initial structure for subsequent molecular dynamics (MD) runs with explicit solvent. We conclude that generating multiple short (∼3 µs) MD simulation trajectories─all starting from the most representative MC generated conformation─and merging them is the protocol of choice due to (i) its ability to satisfy multiple SCCs, (ii) consistently reproducing experimental data, and (iii) the efficiency of running independent trajectories in parallel by harnessing multiple cores available in modern GPU clusters. Running one long trajectory (greater than 20 µs) can also satisfy the first two criteria but is less desirable due to prohibitive computation time. These findings help resolve the challenge of identifying a usable starting configuration, provide an objective measure of SCC, and establish rigorous criteria to determine the minimum length (for one long simulation) or number of trajectories needed in all-atom simulation of IDPs.

Red, Green, and Blue Model-Based Assessment and Principles of White Analytical Chemistry to Robust Stability-Indicating Chromatographic Estimation of Thiocolchicoside and Diclofenac Sodium.

BACKGROUND: White analytical chemistry (WAC) is a recent approach for evaluating analytical procedures based on their effectiveness in validating results, capacity to be environmentally friendly, and economic effectiveness. OBJECTIVE: The detection of diclofenac sodium (DCF) and thiocolchicoside (THC) simultaneously has been established using a WAC-driven stability-indicating chromatographic method (SICM). METHODS: For the concurrent stability study of THC and DCF, the suggested chromatographic technique was developed employing safe and environmentally acceptable organic solvents. To identify critical analytical method parameters (AMPs) and analytical quality attributes (AQAs), a design of experiments (DoE)-based screening design was applied. For the DoE-based response surface modelling (RSM) of critical AMPs and AQAs, the Box-Behnken design (BBD) was employed. RESULTS: A robust SICM was developed by navigating the analytical design space for simultaneous estimation of THC and DCF. IR, NMR, and mass spectral data were used to characterize the degradation products. Red, green, and blue (RGB) models were used to evaluate the suggested method's validation effectiveness, greenness power, and economic efficiency and compared to published chromatographic techniques. The effectiveness of the chromatographic method's validation concerning the International Council for Harmonization (ICH) Q2 (R1) guideline was evaluated using the red model. The analytical greenness (AGREE) evaluation tool and eco-scale assessment (ESA) approach were used to evaluate the green model's methodology. The blue model-based assessment was carried out for comparison of simplicity of instruments handling, cost, and time during sample analysis. The red, blue, and green scores of the techniques were averaged to arrive at the white score of the suggested and reported methods. CONCLUSION: For the concurrent stability study of THC and DCF, the suggested technique was shown to be validated, environmentally friendly, and cost effective. The suggested approach could be a cost-effective and environmentally friendly analytical technique for determining the stability and monitoring the quality of fixed-dose combinations (FDC) of THC and DCF. HIGHLIGHTS: Stability-indicating HPTLC method was developed for concomitant analysis of THC and DCF using concepts of DoE and WAC.

Ultrasound-assisted extraction of hydroxytyrosol and tyrosol from olive pomace treated by gamma radiation: process optimization and bioactivity assessment.

Ultrasound-assisted extraction (UAE) was used to recover hydroxytyrosol and tyrosol from olive pomace, a residue generated by the olive oil industry. The extraction process was optimized using response surface methodology (RSM), with processing time, ethanol concentration and ultrasonic power as the combined independent variables. The highest amounts of hydroxytyrosol (36 ± 2 mg g-1 of extract) and tyrosol (14 ± 1 mg g-1 of extract) were obtained after 28 min of sonication at 490 W using 7.3% ethanol as the solvent. Under these global conditions, an extraction yield of 30 ± 2% was achieved. The bioactivity of the extract obtained under optimized UAE was evaluated and compared with that of an extract obtained under optimal heat-assisted extraction (HAE) conditions in a previous work of the authors. Compared to HAE, UAE reduced the extraction time and the solvent consumption, and also led to higher extraction yields (HAE yield was 13.7%). Despite this, HAE extract presented higher antioxidant, antidiabetic, anti-inflammatory and antibacterial activities and no antifungal potential against C. albicans. Furthermore, HAE extract also showed higher cytotoxic effects against the breast adenocarcinoma (MCF-7) cell line. These findings provide useful information for the food and pharmaceutical industries in developing new bioactive ingredients, which may represent a sustainable alternative to synthetic preservatives and/or additives.

Platform headspace gas chromatography method for high-throughput determination of residual solvents in pharmaceutical materials.

Static headspace capillary gas chromatography (HSGC) has been employed to monitor the level of residual solvents in the pharmaceutical materials. Most of the HSGC methods, however, consume significant amounts of diluents and require considerable amount of sample preparation time. Accordingly, a HSGC method featured with fast turnaround time, and minimal amount of solvent use has been developed for the quantitative analysis of 27 residual solvents frequently used in the development and manufacturing processes of pharmaceutical industry. This HSGC-FID method employs a commercially available fused silica capillary column, a split injection (40:1), and a programmed temperature ramp. It was qualified for specificity, accuracy, repeatability/precision, linearity, LOQ, solution stability, and robustness using two representative sample matrices. The standards, samples and spiked samples were demonstrated to be stable for at least 10 days at room temperature in sealed headspace vials with a recovery of ≥ 93%. The method was also shown to be robust, and its performance was not affected by small changes of carrier gas flow rate, initial oven temperature or the headspace oven temperature. In this new approach, the analytical sample was prepared by dissolving the sample into 1 mL of the diluent and the standard solution was prepared by diluting 1 mL of the custom-made stock into 9 mL of the diluent whereas the traditional approach requires liters of the diluent, making the new approach environmentally friendly, sustainable, economical, agile, error-proofing and thus appropriate for a variety of pharmaceutical applications.

Current Trends in API Co-Processing: Spherical Crystallization and Co-Precipitation Techniques.

Active Pharmaceutical Ingredients (APIs) do not always exhibit processable physical properties, which makes their processing in an industrial setup very demanding. These issues often lead to poor robustness and higher cost of the drug product. The issue can be mitigated by co-processing the APIs using suitable solvent media-based techniques to streamline pharmaceutical manufacturing operations. Some of the co-processing methods are the amalgamation of API purification and granulation steps. These techniques also exhibit adequate robustness for successful adoption by the pharmaceutical industry to manufacture high quality drug products. Spherical crystallization and co-precipitation are solvent media-based co-processing approaches that enhances the micromeritic and dissolution characteristics of problematic APIs. These methods not only improve API characteristics but also enable direct compression into tablets. These methods are economical and time-saving as they have the potential for effectively circumventing the granulation step, which can be a major source of variability in the product. This review highlights the recent advancements pertaining to these techniques to aid researchers in adopting the right co-processing method. Similarly, the possibility of scaling up the production of co-processed APIs by these techniques is discussed. The continuous manufacturability by co-processing is outlined with a short note on Process Analytical Technology (PAT) applicability in monitoring and improving the process.

Determination of toxic elemental levels in whey milk of different cattle and human using an innovative digestion method: risk assessment for children < 6.0 months to 5 years.

In present study, the toxic elements, arsenic (As), cadmium (Cd), and lead (Pb), were determined in whey milk samples obtained from various cattle (cow, goat, buffalo, sheep, camel) and human subjects of different areas of Sindh, Pakistan, based on consuming drinking water (exposed area) and surface water (control/non-exposed area). The whey milk was separated from casein by lowering the pH, and heating in an ultrasonic bath at 60 °C for 5 min and centrifuged. The whey milk samples were treated with deep eutectic solvent, prepared from choline chloride-oxalic acid (ChCl-Ox) at different mole ratio. Effects of different parameters on digestion efficiency of whey milk samples, including time and temperature of electric hot plate, mole ratio, and volumes of deep eutectic solvent were examined. The total levels of all selected toxic elements were also detected in whole milk samples of all exposed and nonexposed cattle and human, after acid digestion method. The validity of the proposed method was established by a conventional acid digestion method of selected whey milk samples and spiked certified standards in replicate real whey milk samples. The resulted elements obtained after proposed and conventional heating system were determined by inductively coupled plasma-optical emission spectrometry. The % of all three toxic elements found in whey milk samples were 24 to 50% of their total content in milk samples of different cattle and human. The As, Cd, and Pb contents in cattle and human milk consumed contaminated groundwater was significantly higher (2- to 3-fold) than those values observed for milk samples of cattle, who receive drinking water from fresh canal water (p < 0.01). Estimating the daily intake, hazard quotient and carcinogenic risk for <6 month to 5 years old children, based on the concentrations of toxic elements in milk samples of different cattle and human..

Validation and green profile assessment of a binary solvent liquid phase microextraction method for the determination of chlorbenside and fenobucarb in lake and wastewater samples by GC-MS.

This study reports a liquid phase microextraction method based on binary extraction solvents, which were used to preconcentrate chlorbenside and fenobucarb from aqueous samples for determination by gas chromatography mass spectrometry. Parameters including the type, ratio, and volume of binary solvents, disperser solvent type and volume, and vortex period were optimized systematically to achieve high enrichment for the analytes. The optimum conditions obtained were used to validate the method, and the detection limits calculated for chlorbenside (0.71 ng/mL) and fenobucarb (0.33 ng/mL) correlated to enrichment factors of 399- and 912-folds, respectively. The optimum method was applied to lake water and wastewater samples in spike recovery experiments, and the results obtained (96-104%) verified the method as accurate and applicable to the aqueous sample matrices. Matrix matching calibration method was used to boost the accuracy of quantifying the two analytes in the wastewater sample, which presented interference effects. Assessment of the method's green profile based on penalty points confirmed the method's compliance with green analytical chemistry.

Assessment of inconsistencies in the solvent-accessible surfaces of proteins between crystal structures and solution structures observed by LC-MS.

Structural proteomics techniques are useful for identifying the binding sites of proteins. The surface of a target protein with and without a bound binding partner is artificially labeled using a hydroxy radical, deuterium, or a low-molecular-weight chemical, and the difference in the label strength with and without the bound partner is determined. Label strength maps are then prepared on the Protein Data Bank (PDB) structure to identify the binding surface. However, the surface-accessible sites determined using such structural proteomics methods are frequently inconsistent with those calculated based on PDB structures, speculating that the measurement determines chemical accessibility rather than solvent accessibility. In this study, the solvent-accessible surface of human serum albumin was analyzed using covalent protein labeling with varying concentrations of CH2O and then compared to surfaces derived from 27 PDB structures. The results indicated that inconsistencies in solvent-accessible surface area values calculated from PDB structures are not caused by the limited capabilities of liquid chromatography-mass spectrometry coupled with covalent protein painting but instead are due to the lack of PDB data representing the structures in solution.

Energy, exergy, economic, environment, exergo-environment based assessment of amine-based hybrid solvents for natural gas sweetening.

Natural gas is the cleanest form of fossil fuel that needs to be purified from CO2 and H2S to diminish harmful emissions and provide feasible processing. The conventional chemical and physical solvents used for this purpose have many drawbacks, including corrosion, solvent loss, high energy requirement, and the formation of toxic compounds, which ultimately disrupt the process and affect the environment. Hybrid solvents have lately been researched to cater to these liabilities and enhance process economics. This study screened eight solvents based on CO2 selectivity viscosity, absorption enthalpy, corrosivity, working capacity, specific heat, and vapor pressure. From the screened solvents, ten cases of hybrid solvents are simulated and optimized on Aspen HYSYS®. Furthermore, 5Es (Energy, Exergy, Economic, Environmental, and Exergy-environmental) analyses were performed on optimized cases, and results were compared with the base case, MEA (30 wt%). The hybrid blend of Sulfolane and MDEA with weight percentages of 6% and 24%, respectively, showed the highest energy savings of 20% concerning the base case. In addition, it offered 93% savings in exergy destruction and 17.26% in the total operating cost of the process. It is also promising to the environment due to reduced entropy sent to the ecosystem and controlled CO2 emissions. Therefore, the blend of Sulfolane and MDEA is proposed to Supersede the conventional solvent MEA for the natural gas sweetening process.

Highly economic and waste valorization strategy for multicomponent and Knoevenagel reactions using water extract of tamarind seed ash.

The application of solid organic waste-originated products in the preparation of synthetically and biologically significant compounds in aqueous media or pure water is a highly desired task in chemical synthesis that shows an effective solution to the circular economy and sustainable environment. In this article, we describe our research on the development of highly economic and sustainable protocols for the synthesis of biologically important oxygen-heterocycles (using a multicomponent reaction) and synthetically important olefins (via the Knoevenagel condensation reaction) using water extract of tamarind seed ash (WETS) as catalyst and aqueous reaction medium. The reactions are carried out at room temperature (RT) under toxic/problematic/volatile organic solvent-free conditions. Products of the current methods have been purified by using recrystallization technique. WETS was characterized from its FTIR, powder XRD, SEM, and EDAX data. Problematic and non-renewable solvents were avoided throughout the process from their synthesis to purification. The utilization of solid organic waste-originated catalyst and aqueous media, avoid of non-renewable substances as catalysts, media, separation solvents and promoters, and unobligating heating conditions can surely attract the attention of chemists towards exploring the waste-based products in chemical transformations.

Spectroscopic characterization and assessment of microbiological potential of 1,3,4-thiadiazole derivative showing ESIPT dual fluorescence enhanced by aggregation effects.

In the presented study, advanced experimental techniques, including electronic absorption and fluorescence spectroscopies [with Resonance Light Scattering (RLS)], measurements of fluorescence lifetimes in the frequency domain, calculations of dipole moment fluctuations, quantum yields, and radiative and non-radiative transfer constants, were used to characterize a selected analogue from the group of 1,3,4-thiadiazole, namely: 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD), intrinsically capable to demonstrate enol → keto excited-states intramolecular proton transfer (ESIPT) effects. The results of spectroscopic analyses conducted in solvent media as well as selected mixtures were complemented by considering biological properties of the derivative in question, particularly in terms of its potential microbiological activity. The compound demonstrated a dual fluorescence effect in non-polar solvents, e.g. chloroform and DMSO/H2O mixtures, while in polar solvents only a single emission maximum was detected. In the studied systems, ESIPT effects were indeed observed, as was the associated phenomenon of dual fluorescence, and, as demonstrated for the DMSO: H2O mixtures, the same could be relatively easily induced by aggregation effects related to aggregation-induced emission (AIE). Subsequently conducted quantum-chemical (TD-)DFT calculations supported further possibility of ESIPT effects. The following article provides a comprehensive description of the spectroscopic and biological properties of the analyzed 1,3,4-thiadiazole derivatives, highlighting its potential applicability as a very good fluorescence probes as well as a compound capable of high microbiological activity.

Fractionation of Raw and Parboiled Rice Husks with Deep Eutectic Solvents and Characterization of the Extracted Lignins towards a Circular Economy Perspective.

In the present work, rice husks (RHs), which, worldwide, represent one of the most abundant agricultural wastes in terms of their quantity, have been treated and fractionated in order to allow for their complete valorization. RHs coming from the raw and parboiled rice production have been submitted at first to a hydrothermal pretreatment followed by a deep eutectic solvent fractionation, allowing for the separation of the different components by means of an environmentally friendly process. The lignins obtained from raw and parboiled RHs have been thoroughly characterized and showed similar physico-chemical characteristics, indicating that the parboiling process does not introduce obvious lignin alterations. In addition, a preliminary evaluation of the potentiality of such lignin fractions as precursors of cement water reducers has provided encouraging results. A fermentation-based optional preprocess has also been investigated. However, both raw and parboiled RHs demonstrated a poor performance as a microbiological growth substrate, even in submerged fermentation using cellulose-degrading fungi. The described methodology appears to be a promising strategy for the valorization of these important waste biomasses coming from the rice industry towards a circular economy perspective.