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Objective: The present study aimed to evaluate the effects of reuterin, a bioactive isolated from the probiotic Lactobacillus reuteri (L. reuteri) on periodontal tissue regeneration, and provide a new strategy for periodontitis treatment in the future. Background: Data discussing the present state of the field: Probiotics are essential for maintaining oral microecological balance. Our previous study confirmed that probiotic L. reuteri extracts could rescue the function of mesenchymal stem cells (MSCs) and promote soft tissue wound healing by neutralizing inflammatory Porphyromonas gingivalis—LPS. Periodontitis is a chronic inflammatory disease caused by bacteria seriously leading to tooth loss. In this study, we isolated and purified reuterin from an extract of L. reuteri to characterize from the extracts of L. reuteri to characterize its role in promoting periodontal tissue regeneration and controlling inflammation in periodontitis. Methods: Chromatographic analysis was used to isolate and purify reuterin from an extract of L. reuteri, and HNMR was used to characterize its structure. The inflammatory cytokine TNFα was used to simulate the inflammatory environment. Periodontal ligament stem cells (PDLSCs) were treated with TNFα and reuterin after which their effects were characterized using scratch wound cell migration assays to determine the concentration of reuterin, an experimental periodontitis model in rats was used to investigate the function of reuterin in periodontal regeneration and inflammation control in vivo. Real‐time PCR, dye transfer experiments, image analysis, alkaline phosphatase activity, Alizarin red staining, cell proliferation, RNA‐sequencing and Western Blot assays were used to detect the function of PDLSCs. Results: In vivo, local injection of reuterin promoted periodontal tissue regeneration of experimental periodontitis in rats and reduced local inflammatory response. Moreover, we found that TNFα stimulation caused endoplasmic reticulum (ER) stress in PDLSCs, which resulted in decreased osteogenic differentiation. Treatment with reuterin inhibited the ER stress state of PDLSCs caused by the inflammatory environment and restored the osteogenic differentiation and cell proliferation functions of inflammatory PDLSCs. Mechanistically, we found that reuterin restored the functions of inflammatory PDLSCs by inhibiting the intercellular transmission of ER stress mediated by Cx43 in inflammatory PDLSCs and regulated osteogenic differentiation capacity. Conclusion: Our findings identified reuterin isolated from extracts of the probiotic L. reuteri, which improves tissue regeneration and controls inflammation, thus providing a new therapeutic method for treating periodontitis. [ABSTRACT FROM AUTHOR]

Helicobacter pylori has a big sway when peptic ulcers are concerned. For its eradication, different protocols have been approved. Among which, the tripartite therapy protocol which embraces vonoprazan as potassium competitive acid blocker in combination with amoxicillin and metronidazole as antibiotics. An environmentally benign HPLC method is addressed in order to simultaneously determine amoxicillin (AMX), metronidazole (MET) and vonoprazan (VPZ) in bulk powder and combined tablet mixture. Full separation of AMX, MET and VPZ is accomplished using C8 column, and a gradient mobile phase system, composed of methanol and phosphate buffer of a pH value of 5. Fine linearity in the concentration ranges 50–600 µg mL−1 amoxicillin, 50–400 µg mL−1 metronidazole and 10–100 µg mL−1 vonoprazan was denoted by the high correlation coefficient (0.9999). The method accuracy and precision are confirmed upon analyzing AMX, MET and VPZ triple therapy not only in their synthetic mixtures and combined tablet mixtures but also in their combined tablet mixtures in simulated gastric fluid. AMX, MET and VPZ triple therapy could be routinely analyzed in QC labs, in case of being co-formulated, using the presented method. Three different assessment tools were adopted revealing the benign environmental impact of presented method. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance of Saussurea species for anti-cancer compounds instigated us to develop chemotherapeutic herbal tablets. This study was an ongoing part of our previous research based on the scientific evaluation of Saussurea heteromalla (S. heteromalla) for anti-cancer lead compounds. In the current study, S. heteromalla herbal tablets (500 /800 mg) were designed and evaluated for anti-cancer activity. Arctigenin was found as a bioactive lead molecule with anti-cancer potential for cervical cancer. The in vitro results on the HeLa cell line supported the ethnopharmacological relevance and traditional utilization of S. heteromalla and provided the scientific basis for the management of cervical cancer as proclaimed by traditional practitioners in China. LD50 of the crude extract was established trough oral acute toxicity profiling in mice, wherein the minimum lethal dose was noticed as higher than 1000 mg/kg body weight orally. Chromatographic fingerprint analysis ensured the identity and consistency of S. heteromalla in herbal tablets in terms of standardization of the herbal drug. About 99.15% of the drug (S. heteromalla crude extract) was recovered in herbal tablets (RSD: 0.45%). In vitro drug release profile was found to be more than 87% within 1 h, which was also correlated with different mathematical kinetic models of drug release (r2 = 0.992), indicating that drug release from matrix tablets into the blood is constant throughout the delivery. The dosage form was found stable after an accelerated stability parameters study which may be used for anti-cervical cancer therapy in the future, if it qualifies successful preclinical investigation parameters. [ABSTRACT FROM AUTHOR]

Quantitative structure-retention relationship (QSRR) modeling has emerged as an efficient alternative to predict analyte retention times using molecular descriptors. However, most reported QSRR models are column-specific, requiring separate models for each high-performance liquid chromatography (HPLC) system. This study evaluates the potential of machine learning (ML) algorithms and quantum mechanical (QM) descriptors to develop QSRR models that can predict retention times across three different reversed-phase HPLC columns under varying conditions. Four machine learning methods—partial least squares (PLS) regression, ridge regression (RR), random forest (RF), and gradient boosting (GB)—were compared on a dataset of 360 retention times for 15 aromatic analytes. Molecular descriptors were calculated using density functional theory (DFT). Column characteristics like particle size and pore size and experimental conditions like temperature and gradient time were additionally used as descriptors. Results showed that the GB-QSRR model demonstrated the best predictive performance, with Q2 of 0.989 and root mean square error of prediction (RMSEP) of 0.749 min on the test set. Feature analysis revealed that solvation energy (SE), HOMO–LUMO energy gap (∆E HOMO–LUMO), total dipole moment (Mtot), and global hardness (η) are among the most influential predictors for retention time prediction, indicating the significance of electrostatic interactions and hydrophobicity. Our findings underscore the efficiency of ensemble methods, GB and RF models employing non-linear learners, in capturing local variations in retention times across diverse experimental setups. This study emphasizes the potential of cross-column QSRR modeling and highlights the utility of ML models in optimizing chromatographic analysis. [ABSTRACT FROM AUTHOR]

Prohibited additives in infant formula severely affect the health of infants. Terahertz (THz) spectroscopy has enormous application potential in analyte detection due to its rich fingerprint information content. However, there is limited research on the mixtures of multiple analytes. In this study, we propose a split ring metasurface that supports magnetic dipole bound states in the continuum (BIC). By breaking the symmetry, quasi-BIC with a high quality (Q) factor can be generated. Utilizing an angle-scanning strategy, the frequency of the resonance dip can be shifted, resulting in the plotting of an envelope curve which can reflect the molecular fingerprint of the analytes. Two prohibited additives found in infant formula, melamine and vanillin, can be identified in different proportions. Furthermore, a metric similar to the resolution in chromatographic analysis is introduced and calculated to be 0.61, indicating that these two additives can be detected simultaneously. Our research provides a new solution for detecting additives in infant formula. [ABSTRACT FROM AUTHOR]

Infections by carbapenemase-producing Enterobacterales constitute a global public health threat. The rapid and efficient diagnosis of Enterobacterales infection is critical for prompt treatment and infection control, especially in hospital settings. We developed a novel loop-mediated isothermal amplification (LAMP) method combined with DNA chromatography to identify five major groups of carbapenemase-producing genes (blaNDM, blaOXA-48-like, blaIMP, blaKPC, and blaVIM). This method uses DNA–DNA hybridization-based detection in which LAMP products can be easily visualized as colored lines. No specific technical expertise, expensive equipment, or special facilities are required for this method, allowing its broad application. Here, 73 bacteria collections including strains with carbapenemase-producing genes were tested. Compared to sequencing results, LAMP DNA chromatography for five carbapenemase-producing genes had a sensitivity and specificity of 100% and >97%, respectively. This newly developed method can be a valuable rapid diagnostic test to guide appropriate treatments and infection control measures, especially in resource-limited settings. [ABSTRACT FROM AUTHOR]

Angelicae Dahuricae Radix (ADR) holds a prominent place in traditional medicine for its remarkable antioxidative, anti-allergic, and antiproliferative capabilities. Recognized within the Korean Pharmacopoeia (KP 12th), Angelica dahurica (Hoffm.) Benth. and Hook.f. ex Franch. and Sav. (AD) and Angelica dahurica var. formosana (H. Boissieu) Yen (ADF) serve as the botanical origins for ADR. Differentiating these two varieties is crucial for the formulation and quality control of botanical drugs, as they are categorized under the same medicinal label. This research utilized two-dimensional high-performance thin-layer chromatography (2D-HPTLC) to effectively distinguish AD from ADF. Additionally, a quantitative analysis reveals significant differences in the concentrations of key active constituents such as oxypeucedanin, imperatorin, and isoimperatorin, with AD showing higher total coumarin levels. We further enhanced our investigative depth by incorporating a DPPH bioautography, which confirmed known antioxidant coumarins and unearthed previously undetected antioxidant profiles, including byakangelicin, byakangelicol, falcarindiol in both AD and ADF, and notably, 2-linoleoyl glycerol detected only in AD as an antioxidant spot. This comprehensive approach affords a valuable tool set for botanical drug development, emphasizing the critical need for accurate source plant identification and differentiation in ensuring the efficacy and safety of herbal medicine products. [ABSTRACT FROM AUTHOR]

This study was conducted to isolate and identify the chemical compounds from the roots of Aloe debrana (L.) and evaluate their antioxidant and antibacterial activities. From the acetone (99.5%) extract of the roots of this plant, four anthraquinones, such as chrysophanol (1), asphodeline (2), aloesaponarin I (5), and laccaic acid D‐methyl ester (6), and a new catechol derivative, 5‐allyl‐3‐methoxybenzene‐1,2‐diol (3), were isolated and elucidated by different chromatographic and spectroscopic methods together with linoleic acid (4), respectively. Compounds 2, 3, and 4 were reported here for the first time from this plant and compound 3 from the genus Aloe. The compounds were evaluated for their antioxidant activity using H2O2 and DPPH assays and bactericidal activity against S. aureus and E. coli. Compounds 3 and 6 showed highest antioxidant activities with IC50 values of 19.38 ± 0.64 and 32.81 ± 0.78 μg/mL in DPPH, and 28.52 ± 1.08 and 27.31 ± 1.46 μg/mL in H2O2, respectively. The isolated compounds also demonstrated considerable activity towards S. aureus. Among these compounds, compound 3 exhibited the highest activity (91.20 ± 0.12% and 9.14 ± 0.93 mm at 1.0 mg/mL) against this bacterium. The overall results suggest that the isolated compounds may be considered as potential sources of the bioactive agents to be used in the pharmacological, food, and other industries. Moreover, their high sensitivity against S. aureus may also support the use of A. debrana plant in the traditional medicine to treat wounds. Therefore, the isolated compounds are responsible for medicinal properties of this plant. [ABSTRACT FROM AUTHOR]

Background: Thesium chinense Turcz. (Named as Bai Rui Cao in Chinese) and its preparations (e.g., Bairui Granules) have been used to treat inflammatory diseases, such as acute mastitis, lobar pneumonia, tonsillitis, coronavirus disease 2019 (COVID-19), and upper respiratory tract infection. However, the material basis, pharmacological efficiency, and safety have not been illustrated. Methods: Anti-inflammatory activity-guided isolation of constituents has been performed using multiple column chromatography, and their structures were elucidated by NMR spectroscopy and ECD calculations. The inhibitory effects on lung inflammation and safety of the crude ethanol extract (CE), Bairui Granules (BG), and the purified active constituents were evaluated using lipopolysaccharide (LPS)-stimulated acute lung inflammation (ALI) mice model or normal mice. Results: Seven new compounds (1–7) and fifty-six known compounds (8–63) were isolated from T. chinense, and fifty-four were reported from this plant for the first time. The new flavonoid glycosides 1–2, new fatty acids 4–5, new alkaloid 7 as well as the known constituents including flavonoid aglycones 8–11, lignans 46–54, alkaloids 34 and 45, coumarins 57, phenylpropionic acids 27, and simple aromatic compounds 39, 44 and 58 exhibited anti-inflammatory activity. Network pharmacology analysis indicated that anti-inflammation of T. chinense was attributed to flavonoids and alkaloids by regulating inflammation-related proteins (e.g., TNF, NF-κB, TGF-β). Furthermore, constituents of T. chinense including kaempferol-3-O-glucorhamnoside (KN, also named as Bairuisu I, 19), astragalin (AG, Bairuisu II, 12), and kaempferol (KF, Bairuisu III, 8), as well as CE and BG could alleviate lung inflammation caused by LPS in mice by preventing neutrophils infiltration and the expression of the genes for pro-inflammatory cytokines NLRP3, caspase-1, IL-1β, and COX-2. After a 28-day subacute toxicity test, BG at doses of 4.875 g/kg and 9.750 g/kg (equivalent to onefold and twofold the clinically recommended dose) and CE at a dose of 11.138 g/kg (equivalent to fourfold the clinical dose of BG) were found to be safe and non-toxic. Conclusions: The discovery of sixty-three constituents comprehensively illustrated the material basis of T. chinense. T. chinense and Bairui Granules could alleviate lung inflammation by regulating inflammation-related proteins and no toxicity was observed under the twofold of clinically used doses. [ABSTRACT FROM AUTHOR]

Nutrient availability in hydroponic solutions must be accurately monitored to maintain crop productivity; however, few cost-effective, accurate, real-time, and long-term monitoring technologies have been developed. In this study, we describe the development and application of cation-/anion-exchange chromatography with a neutral eluent (20-mmol/L sodium formate, pH 7.87) for the simultaneous separation (within 50 min) of ionic nutrients, including K+, NH4+, NO2−, NO3−, and phosphate ion, in a hydroponic fertilizer solution. Using the neutral eluent avoided degradation of the separation column during precipitation of metal ion species, such as hydroxides, with an alkaline eluent and oxidation of NO2− to NO3− with an acidic eluent. The suitability of the current method for monitoring ionic components in a hydroponic fertilizer solution was confirmed. Based on our data, we propose a controlled fertilizer strategy to optimize fertilizer consumption and reduce the chemical load of drained fertilizer solutions. [ABSTRACT FROM AUTHOR]

Chromatographic modeling software packages are valuable tools during method optimization steps. These are well established for reversed‐phase applications utilizing retention time (RT) prediction to optimize separations and receive robust methods, which is of high interest for the analysis of pharmaceuticals. In contrast to liquid chromatography, the knowledge of RT prediction in supercritical fluid chromatography is limited to a manageable number of studies. This study uses the software DryLab to predict the RTs of the peptides bacitracin (Bac), colistin, tyrothricin (Tyro), and insulin analogs. Gradient time, column temperature, and the ternary composition (terC) of carbon dioxide, methanol (MeOH), and acetonitrile (ACN) in the gradient elution are varied in a feasibility approach using a neutral (Viridis BEH) and an amino‐derivatized aromatic (Torus 2‐PIC) stationary phase. In the second part, chromatographic optimization is performed in silico through gradient adjustments to optimize the separation of the fingerprint of Bac. The final gradient method utilizes a Viridis BEH column (100 × 3.0 mm, 1.7 μm), carbon dioxide, and a modifier consisting of ACN/MeOH/water/methanesulfonic acid (60:40:2:0.1, v:v:v:v). In addition, changes in the retention order of Tyro compounds with the proportion of the terC in combination with a Torus Diol column are investigated. [ABSTRACT FROM AUTHOR]

Phosphine ligands are widely used in the manufacture of small molecule active pharmaceutical ingredients, for they play a key role in transition-metal-catalyzed cross-coupling. However, chromatographic analysis of phosphine ligands can be challenging because of the easily oxidizable nature of this class of compounds. This manuscript describes an out-of-specification (OOS) investigation study of XPhos raw material analysis by high performance liquid chromatography (LC). It is concluded that on-column degradation/oxidation is the culprit behind this OOS result. In addition, a slightly modified yet much improved new LC method is developed by adding a trace amount of tris(2-carboxyethyl)phosphine (TCEP) into the aqueous mobile phase. TCEP is also a phosphine compound and is commonly used as a reducing reagent in molecular biology. The trace amount of TCEP serves as a surrogate reagent to passivate the LC column and eliminate the on-column degradation/oxidation. As a result, a much more robust performance is achieved with greatly improved method precision and sensitivity. This is a general approach and can be applied to the LC analysis of many other phosphine ligands in the same manner. [ABSTRACT FROM AUTHOR]

A study on the functionalisation of 2-mercapto-5-methyl-1,3,4-thiadiazole has been conducted, yielding two series of products: 2-(ω-haloalkylthio)thiadiazoles and symmetrical bis-thiadiazoles, with variable chain lengths. The experimental conditions were optimised for each class of compounds by altering the base used and the reagents' proportions, leading to the development of separate protocols tailored to their specific reactivity and purification needs. The target halogenide reagents and bis-thiadiazole ligands were obtained either as single products or as mixtures easily separable by chromatography. Characterisation of the products was performed using 1D and 2D NMR spectra in solution, complemented by single crystal X-ray diffraction (XRD) for selected samples, to elucidate their structural properties. [ABSTRACT FROM AUTHOR]

This study focused on encapsulation of Rosmarinus officinalis essential oil (EO) on chitosan and gum Arabic matrix in various ratios and with varying essential oil concentrations. Additionally, UV/VIS spectroscopy was used to determine cumulative-release profiles. The insecticidal activity was tested against Tribolium castaneum and Oryzaephilus surinamensis, both pests of stored products. In terms of encapsulation efficiency (EE%) and loading capacity (LC%), capsules had EE at 45.8% and LC at 2.31%. Furthermore, many minor compounds were lost after encapsulation, until identifying only 1,8-cineole, α-terpineol, and camphor after 60 d of storage. The fumigant tests demonstrated that encapsulated EO exhibited an effective control against insect pest during storage periods, namely, 30, 45, and 60 d with 99, 66, and 46% mortality for T. castaneum and 100, 84, 82% mortality for O. surinamensis. [ABSTRACT FROM AUTHOR]

Despite significant progress in the development of phototherapy drugs, it is widely recognized that natural products remain the primary source of new photoactive compounds. Exploring uncharted flora in the east‐central region of Argentina may offer a vast array of opportunities to isolate new photoactive molecules or plant extracts with high potential for use in antimicrobial photodynamic therapy (aPDT) against Candida albicans. To assess the photofungicidal potential of T. sinuata ("contrayerba") against C. albicans, the extracts underwent spectroscopic and chromatographic analysis, resulting in the identification of furanocoumarin metabolites with similar spectrophotometric properties in all extracts. The extract profiles were created using UHPLC‐DAD, and seven furanocoumarins (FCs) were detected. The highest photoinactivation against C. albicans was observed for dicholormethanic extracts (MFC = 62.5 μg/mL), equal to xanthotoxin employed as a positive control. Furthermore, we determine that photochemical mechanisms dependent on oxygen (type I and type II processes) and mechanisms independent of oxygen (photoadduct formation) are involved in the death of these yeasts. These results support the use of native plants of the east‐central region of Argentina as potent sensitizers for aPDT and suggest that they can replace xanthotoxin in treating superficial yeast infections of the skin. [ABSTRACT FROM AUTHOR]

Water in the subcritical state is characterized by properties significantly different from water under standard conditions. These include low viscosity, low surface tension, and a much lower dielectric constant, increasing the solubility of nonpolar substances. For this reason, it can provide an alternative solvent and be used in chromatographic techniques—subcritical water chromatography (SBWC). SBWC appears to be one of the greenest analytical techniques until we unravel chromatography with pure water at room temperature. The versatility of SBWC is explored through its applications in the separation and analysis of a wide range of compounds, including pharmaceuticals, natural products, etc. The use of subcritical water as a mobile phase requires suitable stable stationary phases and special apparatus. Still, it makes it possible to conduct analyses without using organic solvents. When using this technique, it is important to remember that it suits the analysis of thermally stable substances. The following work is a critical review of developments in SBWC. [ABSTRACT FROM AUTHOR]

A rapid method to separate Ta, Po, Au, Pt, and W from a sample containing mixed fission and activation products was developed using three commercially available extraction chromatography resins stacked in series. When the separation was tested using all the target activation products, even those with short half-lives were measurable. Combining multiple extraction chromatography resin cartridges in tandem allows for multiple short-lived activation products to be separated from one sample addition without the complication of multiple steps. [ABSTRACT FROM AUTHOR]

Background: Dioscorea bulbifera Linn. has been used for wound care in Thailand. However, a comprehensive evaluation of its antibacterial activity is required. This study aimed to investigate the antibacterial efficacy of D. bulbifera extract against skin-associated bacteria and isolate and characterize its active antibacterial agent, flavanthrinin. Methods: Air-dried bulbils of D. bulbifera were pulverised and extracted with hexane, dichloromethane, ethyl acetate, methanol, ethanol, and distilled water; vacuum filtered; concentrated; freeze-dried; and stored at -20 ºC. Antibacterial activity of the extracts was assessed using microdilution techniques against several skin-associated bacteria. Thin-layer chromatography (TLC) bioautography was used to identify the active compounds in the extract, which were fractionated by column chromatography and purified by preparative TLC. The chemical structures of the purified compounds were analysed using nuclear magnetic resonance (NMR). The cytotoxicity of the extract and its active compounds was evaluated in Vero cells. Results: The ethyl acetate extract exhibited distinct inhibition zones against bacteria compared to other extracts. Therefore, the ethyl acetate extract of D. bulbifera in the ethyl acetate layer was used for subsequent analyses. D. bulbifera extract exhibited antibacterial activity, with minimum inhibitory concentrations (MICs) of 0.78–1.56 mg/mL. An active compound, identified through TLC-bioautography, demonstrated enhanced antibacterial activity, with MICs of 0.02–0.78 mg/mL. NMR analysis identified this bioactive compound as flavanthrinin. Both D. bulbifera extract and flavanthrinin-containing fraction demonstrated potent antibacterial activity against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and S. epidermidis. The flavanthrinin containing fraction demonstrated low cytotoxicity against Vero cells, showing CC50 values of 0.41 ± 0.03 mg/mL. These values are lower than the MIC value, indicating that this fraction is safer than the initial ethyl acetate extract. Conclusions: Dioscorea bulbifera extract and its bioactive component flavanthrinin demonstrated significant antibacterial activity against the skin-associated bacteria Staphylococci, including MRSA. Flavanthrinin has potential as a complementary therapeutic agent for managing skin infections owing to its potent antibacterial effects and low cytotoxicity. [ABSTRACT FROM AUTHOR]

In the presented article, isolation of an antimicrobial Escherichia coli (E. coli) strain from municipal wastewater using high-throughput methods by automated liquid handling is described. The effect of the substance, which is mainly present intracellularly, is directed against the enteropathogenic E. coli (EPEC). Subsequent production and purification of the antimicrobial active substance by heat precipitation, ion exchange chromatography, ammonium sulfate precipitation and hydrophobic interaction chromatography allowed its identification as colicin. This finding is supported by the detection of three different colicin genes in the isolated E. coli strain. The assumed colicin could be purified by a factor of 99, resulting in a very pure sample. The developed platform for the identification and purification of antimicrobial substances from environmental samples can be used for further research and may help to overcome the increasing problems with multidrug-resistant microorganisms. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) is a hydrothermal treatment that converts various types of high moisture biomass into hydrochar. Several operational parameters must be considered, such as temperature, reaction time, biomass/water ratio and initial pressure, which ultimately affect the performance of the process. One of the main advantages of HTC is the possibility to use wet feedstock, which promotes the decrease of the operational energy cost. In this work, Nannochloropsis microalgae was tested for the production of hydrochar. A Batch reactor was used, initially pressurized with 20 bars of nitrogen. A 2k factorial design was used to plan the experiments, with three different factors tested at two different levels: temperature (160-190 ºC), reaction time (30-45 min) and biomass/water ratio (1/10-1/15 w/w). Four different products were obtained: solid fraction (hydrochar), aqueous and gas phases, and an insignificant amount of bio-oil. The gas collected was analyzed by the gas chromatograph to determine the compounds and the mass produced. All the other products were separated by vacuum filtration and decantation, and then weighed to calculate the corresponding product yield. The results indicate that the HTC process is suitable for processing biomass with high moisture content. The reaction temperature was a key parameter that significantly decreased the hydrochar yield, resulting in a higher production of the other products. The effects of reaction time on the hydrochar yield depend on the biomass/water ratio. Overall, HTC process produced a carbon-rich solid and a small amount of gaseous products mainly composed of carbon dioxide. [ABSTRACT FROM AUTHOR]

In recent years, scientific research has faced the numerous problems deriving from the presence of active ingredients in surface and groundwater. Traditional removal methods, such as adsorption and bioremediation, have several disadvantages; thus, in this work, membranes based on cellulose acetate loaded with Fe-N-TiO2, were tested for the photocatalytic degradation of Ceftriaxone Sodium from aqueous solution. The immobilization of the photocatalyst allows to overcome the limits of the photocatalytic process in suspension, which requires expensive and time-consuming post-treatments. Membranes were obtained by supercritical CO2 phase inversion process and were subjected to characterizations such as EDX, TGA, FT-IR, Raman spectroscopy and, subsequently, tested in adsorption tests in the dark and in the presence of visible light, to evaluate their photocatalytic activity. The variations in the concentration of the antibiotic, during the tests conducted, were monitored by HPLC chromatographic analysis. Samples with 10% and 30% by weight of Fe-N-TiO2 demonstrated relatively low adsorption efficiencies of the target contaminant, respectively equal to 22% and 18% in 180 minutes, for reasons related both to the morphology of the samples products, which changes from cellular to finger-like as the photocatalyst load increases, and to the quality of the dispersion. The membrane loaded with 20% by weight of Fe-N-TiO2 allowed a degradation of the model pollutant of 35% in 180 minutes; moreover, the reusability of the membranes was verified. The photocatalytic tests showed that the photocatalytic efficiency was highly correlated to the dispersion of the photocatalyst nanoparticles and to its loading in the polymeric membranes. [ABSTRACT FROM AUTHOR]

Curricula related to instrumental analysis aim for competency-based education to promote the development of teaching strategies that encourage students to successfully tackle the problem-solving and tasks inherent to their profession. However, this endeavor is constrained by the complexity of equipment and the lack of time in laboratory classes. The objective of this work is to present an alternative high-performance liquid chromatography (HPLC) practice that adapts the desired competencies to a shorter and more effective timeframe. It seeks more active participation from the student and contextualizes chromatographic analysis within a real-world problem that encompasses the entire analytical process, from sample to final result. In this scenario, the student receives a solid sample of spicy paprika from a supermarket and must report the level of spiciness in terms of the total amount of capsaicinoids. To achieve this, they must first apply different experimental conditions for extracting the analytes of interest (varying temperatures and solvents) and selecting the most optimal condition. This practice is designed for short sessions, specifically conducted in two 2.5 h laboratory sessions, and has been implemented in the subject "Advanced Techniques in Instrumental Analysis (ATIA)" in the fourth year of the Degree in Biotechnology at the University of Cadiz. The results obtained demonstrated a significant increase in student motivation and an improvement in the acquisition of skills; 100% of the students achieved a grade higher than seven in the final evaluation of their learning process. [ABSTRACT FROM AUTHOR]

Over the years, isolated compounds from medicinal plants have been lead candidates in drug discovery and they are useful therapeutic aid to patients. This work isolated a compound from the seed of Parinari curatellifolia and investigated its inhibitory potential and mechanism on angiotensin-1-converting enzyme (ACE1). The methanolic extract of the seed was subjected to chromatographic techniques and yielded a white, crystalline solid. Structural elucidation of the compound was carried out using NMR and MS spectroscopic techniques. The use of N-(3-[2- furyl-acryloyl]-Phe-Gly-Gly) (FAPGG) as an enzyme substrate and the Michealis-Menten method in this study showed how sensitive and fast ACE1 could be inhibited. Inhibition mechanism was explored using the Lineweaver-Burk model, and IC50 was determined using Cheng-Prusoff empirical analysis. Molecular interaction with ACE1 was investigated computationally. NMR and MS spectroscopy showed the compound to be Akuammine, with 26 protons, 22 carbons, 2 nitrogen, and 4 oxygen atoms and chlorinated molecular ion peak at m/z 417.1593. Akuammine exhibited an IC50 of 8.5 µM and displayed mixed type inhibition. Molecular dynamics simulations indicated strong interaction at the allosteric site of ACE1, primarily through hydrophobic interactions. Akuammine demonstrated an ability as a template for antihypertensive agent. This ability may contribute to the ethno botanical uses of Parinari curatellifolia seed. [ABSTRACT FROM AUTHOR]

For removal of the natural isobar 182W interference prior to ultra-trace 182Hf determination by accelerator mass spectrometry, an extraction chromatographic method for separation of Hf from W has been developed by using a newly synthesized tri-n-octylamine (TOA)/XAD-7 resin as the stationary phase and HCl-HF media as the mobile phase. Based on the TOA liquid-liquid extraction studies in HF and HCl-HF solutions at wide concentration range, a maximum separation factor of 8.6 × 103 for W/Hf was obtained in 8 M HCl-0.05 M HF solution. Subsequently, the macroporous organic polymer-based TOA/XAD-7 resin was prepared by vacuum impregnation technique and its morphology, chemical structure and composition were characterized by SEM, EDS, FT-IR, TG-DSC, and EA. The results showed the self-assembly TOA/XAD-7 resin uptakes about 50% of extractant and keeps intact binding characteristic for metal ions. Hence, this resin was employed to investigate the column chromatographic behavior of Hf and W with variable parameters of sample loading and column bed dimensions. As a result, a high yield of more than 99% for Hf and high decontamination factor of 3.2 × 105 for W were achieved under the optimal column condition. The strategy developed provides a simple and efficient alternative to sample preparation for 182Hf measurement. [ABSTRACT FROM AUTHOR]

Multivalent pneumococcal vaccines have been developed successfully to combat invasive pneumococcal diseases (IPD) and reduce the associated healthcare burden. These vaccines employ pneumococcal capsular polysaccharides (PnPs), either conjugated or unconjugated, as antigens to provide serotype-specific protection. Pneumococcal capsular polysaccharides used for vaccine often contain residual levels of cell wall polysaccharides (C-Ps), which can generate a non-serotype specific immune response and complicate the desired serotype-specific immunity. Therefore, the C-P level in a pneumococcal vaccine needs to be controlled in the vaccine process and the anti C-P responses need to be dialed out in clinical assays. Currently, two types of cell-wall polysaccharide structures have been identified: a mono-phosphocholine substituted cell-wall polysaccharide C-Ps1 and a di-phosphocholine substituted C-Ps2 structure. In our effort to develop a next-generation novel pneumococcal conjugate vaccine (PCV), we have generated a monoclonal antibody (mAb) specific to cell-wall polysaccharide C-Ps2 structure. An antibody-enhanced HPLC assay (AE-HPLC) has been established for serotype-specific quantification of pneumococcal polysaccharides in our lab. With the new anti C-Ps2 mAb, we herein extend the AE-HPLC assay to the quantification and identification of C-Ps2 species in pneumococcal polysaccharides used for vaccines. [ABSTRACT FROM AUTHOR]

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Renewable lignocellulosic biomass is a favorable energy resource since its co-pyrolysis with hydrogen-rich plastics can produce high-yield and high-quality biofuel. In contrast to earlier co-pyrolysis research that concentrated on increasing product yield, this study comprehends the synergistic effects of two distinct feedstocks that were not considered earlier. This work focuses on co-pyrolyzing wheat straw (WS) with non-reusable polyethylene terephthalate (PET) for the production of pyrolysis oil. WS and PET were blended in different ratios (100/0, 80/20, 60/40, 40/60, 20/80, and 0/100), and pyrolysis experiments were conducted in a fixed-bed reactor under different temperatures to assess their synergistic effect on oil yield. Synergy rates of up to 7.78 % were achieved on yield for the blends of plastic and biomass at a temperature of 500 °C. In comparison to individual biomass or plastics, co-pyrolyzing PET-biomass blends demonstrated good process interaction and promoted the yields of value-added products. The heating value of the pyrolysis oils was in the range of 16.45–28.64 MJ/kg, which depends on the amount of plastic present in the feedstock. The physical analysis of the oils shows that they can be used for heat production by direct combustion in boilers or furnaces. The correlation between WS and PET was validated with the aid of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) analysis. The GC-MS result demonstrated the presence of different compounds such as O-H compounds, esters, carbonyl group elements, acids, hydrocarbons, aromatics, and nitrogenated compounds in the pyrolysis oil, which differed based on the proportions of PET in the feedstock. The increased hydrocarbon and reduced oxygen percentages in the pyrolysis oil were implicitly caused by enhanced hydrocarbon pool mechanisms, in which the breakdown of PET may be supplied as a hydrogen donor. Overall, waste lignocellulosic biomass and plastics can be used to produce biofuels, which helps reduce the amount of solid waste that ends up in landfills. This study also revealed that future research should be focused on the reaction mechanisms of WS and PET co-pyrolysis in order to examine the synergistic interactions.

Abstract Therapeutic drug monitoring is an important clinical testing of the drugs to monitor their concentrations in plasma in order to guarantee their optimal impact, and to avoid any side effects resulting from drug-drug interactions. A green reversed-phase high-performance liquid chromatographic method using a photodiode array detector (RP-HPLC-PDA) was developed for the simultaneous determination of three carbapenem antibiotics (Imipenem, ertapenem, and meropenem) with the co-formulated drug (cilastatin) and contraindicated drugs (probenecid and warfarin) in spiked human plasma. The separation was achieved at 25 °C using a gradient elution of a mixture of mobile phase A: methanol and mobile phase B: phosphate buffer (pH 3.0). The photodiode array detector was adjusted at 220 nm. Bioanalytical method validation was carried out as per the FDA guidelines, and the method showed good linearity ranges for the six drugs that included their Cmax levels along with low limits of quantification. Based on the results, the method was found to be accurate and precise; with high % recovery and good % RSD, respectively. The method was successfully applied to spiked human plasma, signifying a good potential to be implemented in future TDM studies of these drugs when co-administered together.

The electronic state chromatography (ESC) effect allows the differentiation of ions in their ground and metastable states by their gaseous mobilities in the limit of low electrostatic fields. It is investigated here by means of accurate transport calculations with ab initio ion–atom potentials for the Cr, Co, and Ni cations in He buffer gas near room temperature. The values for the open-shell ions in degenerate states are shown to be well approximated by using the single isotropic interaction potential. Minimalistic implementation of the multireference configuration interaction (MRCI) method is enough to describe the zero-field transport properties of metastable ions in the 3dm−14s configuration, such as Cr+(a6D), Co+(a5F), and Ni+(4F), due to their weak and almost isotropic interaction with He atom and the low sensitivity of the measured mobilities to the potential well region. By contrast, interactions involving the ions in the ground 3dm states, such as Cr+(a6S), Co+(a3F), and Ni+(2D), are strong and anisotropic; the MRCI potentials poorly describe their transport coefficients. Even the coupled cluster with singles, doubles, and non-iterative triples approach taking into account vectorial spin–orbit coupling may not be accurate enough, as shown here for Ni+(2D). The sensitivity of ion mobility and the ESC effect to interaction potentials, similarities in ion–He interactions of the studied ions in distinct configurations, accuracy and possible improvements of the ab initio schemes, and control of the ESC effect by macroscopic parameters are discussed. Extensive sets of improved interaction potentials and transport data are generated. [ABSTRACT FROM AUTHOR]

Heating tert-butyl-tetraline with [(p-cymene)RuCl2]2 produces the racemic complex [(arene)RuCl2]2, which can be separated into enantiomers by chromatography of its diastereomeric adducts with chiral phosphine ligand. The resolved chiral complex catalyzes C--H activation of N-methoxy-benzamides and their annulation with N-vinyl-pivaloyl amide giving dihydroisoquinolones in 50-80% yields and with 40-80% enantiomeric excess. [ABSTRACT FROM AUTHOR]

Objective. Matrix metalloproteinase-2 (MMP2) overexpression has been considered as a hallmark of tumor aggressiveness. The significant roles of MMP2 in other human disorders, such as cardiovascular diseases and dental caries, have also been demonstrated. Herein, we used in silico approaches to evaluate the binding affinity of selected cinnamic acids to the MMP2 catalytic domain. The obtained findings were subsequently juxtaposed with those attributed to oleandrin, utilized as a reference pharmaceutical agent. Methods. This research employed the AutoDock software to assess the affinity of 19 herbal compounds derived from cinnamic acid to the catalytic cleft of MMP2. The ligands attaining the most negative scores, as determined by the Gibbs free binding energy assessments, were accorded the highest rankings. The interactions between the MMP2 and cinnamic acids ranked highest were elucidated using the Discovery Studio Visualizer tool. Molecular dynamics simulations were performed to investigate the structural stability of MMP2 backbone atoms when forming complexes with both the top-ranked inhibitor from this study and a standard drug. Results. Eight cinnamic acids were indicated with Δ G binding values less than −10 kcal/mol. Cynarin emerged as the most potent inhibitor of the enzyme, with the Δ G binding score and inhibition constant value of −15.19 kcal/mol and 7.29 pM, respectively. The MMP2 backbone atoms achieve stability around the 20 ns mark, displaying a root mean square deviation of approximately 3.2 Å when influenced by the top-ranked cinnamic acid, the standard drug, or in their free form. Conclusion. The inhibition of MMP2 by cinnamic acids, particularly cynarin, holds promise as a valuable therapeutic strategy for various human disorders, encompassing cancer, cardiovascular conditions, and dental caries. [ABSTRACT FROM AUTHOR]

Purpose. The Gram-positive Staphylococcus aureus bacterium is one of the leading causes of infection in humans. The lack of specific noninvasive techniques for diagnosis of staphylococcal infection together with the severity of its associated complications support the need for new specific and selective diagnostic tools. This work presents the successful synthesis of an immunotracer that targets the α-toxin released by S. aureus. Methods. [89Zr]Zr-DFO-ToxAb was synthesized based on radiolabeling an anti-α-toxin antibody with zirconium-89. The physicochemical characterization of the immunotracer was performed by high-performance liquid chromatography (HPLC), radio-thin layer chromatography (radio-TLC), and electrophoretic analysis. Its diagnostic ability was evaluated in vivo by positron emission tomography/computed tomography (PET/CT) imaging in an animal model of local infection-inflammation (active S. aureus vs. heat-killed S. aureus) and infective osteoarthritis. Results. Chemical characterization of the tracer established the high radiochemical yield and purity of the tracer while maintaining antibody integrity. In vivo PET/CT image confirmed the ability of the tracer to detect active foci of S. aureus. Those results were supported by ex vivo biodistribution studies, autoradiography, and histology, which confirmed the ability of [89Zr]Zr-DFO-ToxAb to detect staphylococcal infectious foci, avoiding false-positives derived from inflammatory processes. Conclusions. We have developed an immuno-PET tracer capable of detecting S. aureus infections based on a radiolabeled antibody specific for the staphylococcal alpha toxins. The in vivo assessment of [89Zr]Zr-DFO-ToxAb confirmed its ability to selectively detect staphylococcal infectious foci, allowing us to discern between infectious and inflammatory processes. [ABSTRACT FROM AUTHOR]

The goal of this study was to apply the principles of analytical quality by design (AQbD) to the analytical method for determining the radiochemical purity (PQR) of the radiopharmaceutical sodium iodide 131I oral solution, utilizing thin-layer chromatography (TLC) with a radio–TLC scanner, which also enables the evaluation of product quality. For AQbD, the analytical target profile (ATP), critical quality attributes (CQA), risk management, and the method operable design region (MODR) were defined through response surface methodology to optimize the method using MINITAB® 19 software. This study encompassed the establishment of a control strategy and the validation of the method, including the assessment of selectivity, linearity, precision, robustness, detection limit, quantification limit, range, and the stability of the sample solution. Under the experimental conditions, the method parameters of the TLC scanner were experimentally demonstrated and optimized with an injection volume of 3 µL, a radioactive concentration of 10 mCi/mL, and a carrier volume of 40 µL. Statistical analysis confirmed the method's selectivity for the 131I iodide band Rf of 0.8, a radiochemical impurity IO3− Rf of 0.6, a linearity from 6.0 to 22.0 mCi/mL, and an intermediate precision with a global relative standard deviation (RSD) of 0.624%. The method also exhibited robustness, with a global RSD of 0.101%, a detection limit of 0.09 mCi/mL, and a quantification limit of 0.53 Ci/mL, meeting the prescribed range and displaying stability over time (at 0, 2, and 20 h) with a global RSD of 0.362%, resulting in consistent outcomes. The development of a method based on AQbD facilitated the creation of a design space and an operational space, with comprehensive knowledge of the method's characteristics and limitations. Additionally, throughout all operations, compliance with the acceptance criteria was verified. The method's validity was confirmed under the established conditions, making it suitable for use in the manufacturing process of sodium iodide 131I and application in nuclear medicine services. [ABSTRACT FROM AUTHOR]

Vacuum‐assisted headspace solid‐phase microextraction (Vac‐HS‐SPME) is a technique used to enhance SPME sampling of semi‐volatile organic compounds. Here, it was combined with a high‐capacity SPME Arrow, which features a larger volume of extraction phase and a more rugged configuration than traditional extraction fibers. An in‐depth assessment of the critical parameters was conducted to achieve optimal extraction of representative compounds from a model solid sample matrix (Ottawa sand). Operational fundamentals investigated included the types of seals needed to create a leak‐free environment under vacuum conditions; the magnitude of the vacuum applied and time needed to activate the Vac kinetics; order of sample vial preparation methods (VPMs); and other standard variables associated with extract analysis by gas chromatography‐mass spectrometry. When exploring the limits of sample VPMs, results indicated an ideal workflow requires the solid sample to be spiked before sealing the vial, allow the sample to rest overnight, then apply vacuum at a pressure of ‐677 mbar (out of ‐789 mbar maximum possible vacuum with pump and compressor used), exerted on the vial for 90 s. This work provides the necessary workflow for the optimization of Vac‐HS‐SPME sampling of analytes from solid matrices. [ABSTRACT FROM AUTHOR]

This study presents an innovative method for caffeine determination in tea, employing ethanol as the sole organic solvent for both SPE sample preparation and chromatographic analysis. This approach aligns with green chemistry principles, as confirmed by a comparative study highlighting ethanol's safety and eco-friendliness compared to traditional solvents. The experiments validate ethanol's efficacy in caffeine extraction and chromatographic analysis, minimizing environmental impact and eliminating toxicity risks. Utilizing a reduced chromatography column enhances the method's efficiency and sustainability, resulting in a low limit of quantitation (0.125 μg/mL) and good reproducibility (RSD < 2.5%). Based on tea from the Polish market, the findings reveal the caffeine content (19.29–37.69 mg/g) and endorse ethanol's role in enhancing sustainable chemical analysis in food science. [ABSTRACT FROM AUTHOR]

For various purposes, it is required to compress the shape of the molecular weight distribution (MWD) of polymers into a limited set of parameters. With increasing molecular weight and polydispersity, the MWD data obtained from chromatography become increasingly unreliable due to deficiencies in the high molecular weight region, making estimation via melt rheology more preferable. A number of empirical parameters obtained from melt rheology can be related back to MWD parameters. The target of this study is to establish the reliability of such relations for polypropylene homo‐ and copolymers. It is found that correlations between polydispersity from rheological crossover modulus and polydispersity via chromatography are not always valid. Therefore, the range of applicability must be kept in mind when attempting predictions based on these correlations because rheological measurements are sensitive to molecular characteristics in ways different from chromatography. The use of a modified polydispersity index is shown to be more reliable. [ABSTRACT FROM AUTHOR]

Advances in the design of novel porous materials open new avenues for the development of chromatographic solid stationary phases. Covalent organic frameworks (COFs) are promising candidates in this context due to their remarkable structural versatility and exceptional chemical and textural properties. In this minireview, we summarize the main strategies followed in recent years to apply these materials as stationary phases for chromatographic separations. We also comment on the perspectives of this new research field and potential directions to expand the applicability and implementation of COF stationary phases in analytical systems. [ABSTRACT FROM AUTHOR]

Therapeutic drug monitoring is an important clinical testing of the drugs to monitor their concentrations in plasma in order to guarantee their optimal impact, and to avoid any side effects resulting from drug-drug interactions. A green reversed-phase high-performance liquid chromatographic method using a photodiode array detector (RP-HPLC-PDA) was developed for the simultaneous determination of three carbapenem antibiotics (Imipenem, ertapenem, and meropenem) with the co-formulated drug (cilastatin) and contraindicated drugs (probenecid and warfarin) in spiked human plasma. The separation was achieved at 25 °C using a gradient elution of a mixture of mobile phase A: methanol and mobile phase B: phosphate buffer (pH 3.0). The photodiode array detector was adjusted at 220 nm. Bioanalytical method validation was carried out as per the FDA guidelines, and the method showed good linearity ranges for the six drugs that included their Cmax levels along with low limits of quantification. Based on the results, the method was found to be accurate and precise; with high % recovery and good % RSD, respectively. The method was successfully applied to spiked human plasma, signifying a good potential to be implemented in future TDM studies of these drugs when co-administered together. [ABSTRACT FROM AUTHOR]

A Quantitative structure-retention relationship (QSRR) analysis has been performed on the chromatography parameters of lipophilicity of selected spirohydantoins. Multiple linear regression (MLR) was applied to construct the QSRR models. The chromatographic parameters of lipophilicity were determined by reversed-phase thin-layer chromatography. Chromatographic analyses were performed on C-18 modified silica gel with a two-component mobile phase consisting of water and protic organic solvent (ethanol, n-propanol, i-propanol, or t-butanol) in different ratios. QSRR models were also created for additional four aqueous mobile phases: acetone-water, acetonitrile-water, tetrahydrofuran-water, and 1,4-dioxane-water (results published before). In total, chromatographic lipophilicity parameters obtained for two types of organic solvents were subject of the QSRR. The predictive ability of each model was evaluated using internal and external validation. The best QSRR model for predicting the chromatographic parameter of lipophilicity was obtained for tetrahydrofuran as an organic solvent. [ABSTRACT FROM AUTHOR]

In this work, a green and practical analytical method based on natural deep eutectic solvents (NADES) as extraction agents and nano-liquid chromatography as a separation technique was developed. To demonstrate the applicability of the methodology, alkylphenols and bisphenol A were evaluated as model compounds in olive and sunflower oils as model fatty samples by liquid–liquid microextraction. With this aim, several NADES based on mixtures of choline chloride with glycerol, lactic, ascorbic, and citric acids or glycerol with amino acids were evaluated as potential extraction solvents. In addition, to select the most suitable stationary phase for the separation of this group of contaminants, some stationary phases were tested, including Pinnacle II phenyl, Cogent Bidentate C18™, and XBridge® C18. The last one provided the best performance with an analysis time of 11 min. To solve the problem of the compatibility of hydrophilic NADES with chromatographic systems without harming the solubility of analytes, different aqueous organic mixtures were tested. Methanol/water mixtures were the most suitable as an injection solvent. Finally, following the White Analytical Chemistry principles, different tools were used to evaluate the greenness, the practicality, and applicability of the method based on the Analytical Eco-Scale, the Analytical GREEnness metric approach, and the Blue Applicability Grade Index. [ABSTRACT FROM AUTHOR]

In the current study, chromatographic and in silico techniques were applied to investigate the biotransformation of ethyl 5-(4-bromophenyl)-1-(2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxoethyl)-2-methyl-1H-pyrrole-3-carboxylate (11b) in hepatocytic media. The initial chromatographic procedure was based on the employment of the conventional octadecyl stationary phase method for estimation of the chemical stability. Subsequently, a novel and rapid chromatographic approach based on a phenyl–hexyl column was developed, aiming to separate the possible metabolites. Both methods were performed on a Dionex 3000 ThermoScientific (ACM 2, Sofia, Bulgaria) device equipped with a diode array detector set up at 272 and 279 nm for analytes detection. An acetonitrile: phosphate buffer of pH 3.5: methanol (17:30:53 v/v/v) was eluted isocratically as a mobile phase with a 1 mL/min flow rate. A preliminary purification from the biological media was achieved by protein precipitation with methanol. A validation procedure was carried out, where the method was found to correspond to all ICH (Q2) and M10 set criteria. Additionally, an in silico-based approach with the online server BioTransformer 3.0 was applied in an attempt to predict the possible metabolites of the title compound 11b. It was hypothesized that four CYP450 isoforms (1A2, 2C9, 3A4, and 2C8) were involved in the phase I metabolism, resulting in the formation of 12 metabolites. Moreover, docking studies were conducted to evaluate the formation of stable complexes between 11b and the aforementioned isoforms. The obtained data indicated three metabolites as the most probable products, two of which (M9_11b and M10_11b) were synthesized by a classical approach for verification. Finally, liquid chromatography with a mass detector was implemented for comprehensive and summarized analysis, and the obtained results revealed that the metabolism of the 11b proceeds possibly with the formation of glucuronide and glycine conjugate of M11_11b. [ABSTRACT FROM AUTHOR]

Dimethyl sulfides are ubiquitous odorous substances in eutrophic freshwater bodies. In this study, a simple headspace solid-phase microextraction-gas chromatography-flame photometric detection method was developed to detect three representative algal-derived dimethyl sulfides in freshwater lake water samples: dimethyl monosulfide (DMS), dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS). The effects of extraction fiber, temperature, pH, ionic strength, and sample volume were investigated orthogonally, and the optimized method was applied to analyze surface water samples from Lake Ulansuhai in Inner Mongolia, China. Optimal extraction was obtained with a 50/30 µm DVB/CAR/PDMS extraction fiber, 20% ion concentration, 87 min extraction time, and 50 °C extraction temperature. The correlation coefficients of the standardized working curves for DMS, DMDS, and DMTS were 0.9967, 0.9907, and 0.9994, respectively, indicating good linear relationships. Limits of detection were in the nanogram range, and the recoveries of the spiked standards for DMS, DMDS, and DMTS were 97.22~99.07%, 93.39~99.34%, and 91.17~99.25%, with relative standard deviations of 5.18~5.94%, 3.08~6.25%, and 2.56~5.47%, respectively. This method is stable and reliable, and can be used for the determination of volatile sulfides in freshwater lake water. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to develop a simple, accurate, and precise method for the estimation of bupropion and dextromethorphan in a fixed-dose combination of tablets and robust high-performance liquid chromatography for assay analysis of such a fixed combination. Materials and Methods: Chromatographic analysis was performed and separations were achieved on a Denali C18 150 × 4.6 mm, 5 micron using a mobile phase composition of ortho-phosphoric acid and acetonitrile in the ratio of 600:400 (v/v), flow rate of 1.0 mL/min, injection volume is 10 µL and run time of 6 min in isocratic elution. Ultraviolet (UV) detection was performed at a wavelength of 221 nm. The temperature was maintained at 30 °C. Well-resolved peaks were observed with a high number of theoretical plates, lower tailing factor, and reproducible relative retention time. The method was validated, and all validation parameters were found to be within the acceptance limits. Results: A simple, accurate, and precise method has been developed for estimating bupropion and dextromethorphan in a fixed dose combination of tablets. The optimized method included the following parameters: column temperature of 30 °C, 40% acetonitrile as the mobile phase, and flow rate of 1.0 mL/min. Retention times were 2.25 min and 3.12 min for bupropion and dextromethorphan, respectively. The method was found to be linear in the range of 17.5-105 µg/mL [for R2 < 0.999) and 7.5-45 µg/mL (for R2 > 0.999] for bupropion and dextromethorphan, respectively. Both active pharmaceutical ingredients dissolved more than 90% within 5 min. Conclusion: The current study describes a new, simple, reliable, and economical elution reversed-phase high performance liquid chromatography method for estimating bupropion and dextromethorphan in a fixed combination tablet dosage form. The forced degradation studies were conducted using several degradation conditions such as acidic, alkali, oxidation, thermal, UV, and neutral conditions; the proposed method was effectively employed from the resolution of sample peaks. To the best of our knowledge, no such detailed and stability-indicating method has been reported for a fixed tablet dosage form. [ABSTRACT FROM AUTHOR]

The pinyon pines, Pinus edulis (two-needle pinyon pine) and Pinus monophylla (single-leaf pinyon pine) are conspicuous trees in the pinyon-juniper woodlands of the Great Basin. The purpose of this study is to examine the volatile phytochemicals in the leaf essential oils of P. edulis and P. monophylla, including enantiomeric distribution of the chiral monoterpenoids. Leaves (needles) of P. edulis and P. monophylla were collected in Utah and the essential oils were obtained by hydrodistillation. Gas chromatographic analysis revealed the major components to be α-pinene (13.1-36.5% and 27.8-29.0%, respectively), β-pinene (6.2-34.8% and 11.2-23.4%), β-phellandrene (9.5-20.2% and 11.9-14.7%), and α-terpineol (3.8-6.8% and 6.2-9.2%). Enantioselective gas chromatography showed (–)-β-pinene (> 95%), (–)-β-phellandrene (> 98%), and (–)-α-terpineol (53.6-93.0%) to be the dominant enantiomers while α-pinene showed some variability (39.5-88.9% (+)-α-pinene). The enantiomeric distributions of chiral terpenoids are presented for these essential oils for the first time and adds to our understanding of Pinus essential oils. However, additional research is needed to investigate the enantiomeric distributions of chiral terpenoids of Pinus essential oils more fully. [ABSTRACT FROM AUTHOR]