查找使用阿拉丁产品的科研文献

Rapid determination of alendronate to quality evaluation of tablets by high resolution 1H NMR spectroscopy

Baogang Xie,Aihong Liu,Xiuzhong Fang,Ying Chen,Haijun Zhong

Determination of alendronate is crucial to routine quality control of alendronate tablets. However, tedious sample treatment processes such as derivatization were generally required by chromatographic separation of alendronate as its high polarity and no chromophore in the molecular structure. Here, we describe the use of 1 H NMR for the quantification of alendronate sodium in tablets. Linearity, recovery, selectivity and sensitivity of the assay were validated to be satisfactory with quick sample preparation and acquisition. The contents of alendronate sodium in tablets from five manufacturers were determined, the results showed that all assayed tablets fell within the range of 90.0–110.0% of the label claim and the relative standard deviation was less than 6.0%. The method was also successfully employed for alendronate tablet dissolution assay in this study.

l-Proline-catalyzed synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones in ionic liquids

Wang Yun,Zhang Qiang-qiang,Liu Zi-yin,Xie Zhuang-dong

The synthesis of 2-aryl-2,3-dihydroquinolin-4(1 H )-ones from aromatic aldehydes and and 1-(2-aminophenyl)ethanone catalyzed by l -proline in ionic liquids was achieved for the first time. High yields up to 88.7% were achieved. Mild reaction conditions, enhanced rates, improved yields, and reagents’ reactivity, which is different from that in standard organic solvents, are the remarkable features observed in ionic liquids. In addition, the reaction mechanism was studied using computational methods, and the results were consistent with experimental findings. Graphical abstract

Enhanced chlorine photolysis and 1H-benzotriazole Degradation in Water under the Far-UVC (UV222) irradiation

Jia-Jing Lyu,Qing Bai,Qian-Yuan Wu,Yu-Jia Nong,Mu-Da Han,Min-Yong Lee,Zhong-Quan Ren,Jiang-Lei Xiong,Wen-Long Wang

Far-UVC at 222   nm (UV 222 ) is a promising alternative of conventional 254   nm (UV 254 ) lamps for microorganism inactivation and recalcitrant pollutant removal. This study evaluates UV 222 combined with chlorine (HOCl/OCl⁻) for removing 1H-benzotriazole (BTZ), a widely used UV-absorber and anticorrosion agent ubiquitously detected in wastewater, surface water, and swimming pools. UV 222 achieved 1.4−21.7 times faster direct photolysis of BTZ compared to UV 254 , attributed to higher quantum yield (3.0−32.4 enhancement). UV 222 /chlorine demonstrated strong synergies (factors of 3.7–16.3 across pH 5.0–10.0), consistently outperforming UV 254 /chlorine by 1.09–2.02-fold. Kinetic modeling revealed that UV 222 generates reactive radicals more efficiently, with innate quantum yields for HOCl and OCl⁻ photolysis being 1.7-fold and 4.0-fold higher than UV 254 , respectively, resulting in elevated steady-state concentrations of • OH, Cl • , and ClO • . Reactive chlorine species contributed 47.5%–72.9% to BTZ degradation. Notably, under alkaline conditions where OCl⁻ dominates, UV 222 /chlorine showed substantially greater advantage over UV 254 /chlorine, as UV 222 appears to mitigate the marked reduction in OCl⁻ efficiency. In complex water matrices, nitrate (≥0.5   mM) acted as a photosensitizer, enhancing BTZ removal, while humic acid caused moderate inhibition (16.8%−44.0%). In tap water and secondary effluent, UV 222 /chlorine achieved 1.39–3.86 times higher degradation than in deionized water, with nitrate-driven radical generation outweighing natural organic matter inhibition. Importantly, UV 222 /chlorine produced 23% lower chlorinated disinfection byproducts (DBPs) and 17% lower toxicity-index than UV 254 /chlorine, demonstrating its potential as an alternative of UV 254 -driven oxidation process.

1H LF-NMR study on water migration behavior of fresh cement paste with limestone powder

Jing Qiao,Chunsheng Zhou,Jingjing Feng,Miao Miao,Yanliang Ji,Linan Gu

Limestone powder (LS) with large particle sizes is widely used, but its effect on water migration behavior remains unclear. This study investigates the influence of LS and viscosity-enhancing admixtures (VEAs) on the water migration behavior and water distribution in fresh cement paste using 1 H low-field nuclear magnetic resonance (LF-NMR). Results indicate that LS increases the size of water migration channels, accelerates the water migration rate, and raises the bleeding ratio, while VEAs substantially mitigate the effects of LS. Compared to polyacrylamide, cellulose ether significantly slows down the water migration rate before 40 min, thereby reducing the bleeding ratio. Additionally, relaxation times were found to decrease during bleeding and can reflect the sedimentation process. It is confirmed that the pore structure of fresh paste exhibits fractal characteristics, with the fractal dimension closely correlating with water migration rates. The underlying mechanisms and their implications on material behavior are thoroughly analyzed and discussed.

NCS-catalyzed synthesis of 2,4,5-triaryl-1H-imidazole and its selective detection of iron ions

Chang Liu,Lu Ren,Jing Wang,Ping Wu,Yanqi Liu,Yujie Shang,Dawei Zhang

In this study, an efficient synthesis of 2,4,5-trisubstituted imidazoles was developed via cyclocondensation starting from o -dione, substituted aromatic aldehyde and ammonium acetate using catalyst NCS, and was characterized by HR-MS, FT-IR, 1 H and 13 C NMR spectroscopy. A novel fluorescence sensor 4-(1 H -phenanthro[9,10- d ]imidazol-2-yl)- N, N -diphenylaniline ( 3bd ) was discovered for the detection of Fe 3+ ions. The probe 3bd exhibited strong blue radiation in solution. In the presence of Fe 3+ ions, a significant fluorescence change of blue light to green light was observed in the EtOH/H 2 O (4/1, v/v) solution of 3bd (Ag + , Al 3+ , Ba 2+ , Ca 2+ , Cd 2+ , Co 2+ , Cr 3+ , Cu 2+ , Fe 2+ , Fe 3+ , Hg 2+ , Mg 2+ , Mn 2+ , Pb 2+ , Sr 2+ , Zn 2+ ). The limits of detection of probe 3bd for Fe 3+ ions was calculated to be as low as 0.70 μ M, and it had excellent anti-interference ability. The probe 3bd complexed with Fe 3+ ions at 1:1, and the complexation constant was 3.93 × 10 4 M −1 . The probe 3bd realized the detection of Fe 2+ oxidation to Fe 3+ , and the pH showed fine stability in the environment between 4.0–7.0, which ensured its potential application prospects. It also showed good reversibility upon addition of EDTA. Furthermore, the viability of 3bd to Fe 3+ had practical application in live cell imaging.

Discovery of N-hydroxy-4-(1H-indol-3-yl)butanamide as a histone deacetylase inhibitor

Jiang Bian,Yepeng luan,Chunbo Wang,Lei Zhang

Quantitative determination and validation of octreotide acetate using 1H-NMR spectroscopy with internal standard method

Chen Yu,Qian Zhang,Peng-yao Xu,Yin Bai,Wen-bin Shen,Bin Di,Meng-xiang Su

Quantitative nuclear magnetic resonance (qNMR) is a well-established technique in quantitative analysis. We presented a validated 1 H-qNMR method for assay of octreotide acetate, a kind of cyclic octopeptide. Deuterium oxide was used to remove the undesired exchangeable peaks, which was referred to as proton exchange, in order to make the quantitative signals isolated in the crowded spectrum of the peptide and ensure precise quantitative analysis. Gemcitabine hydrochloride was chosen as the suitable internal standard. Experimental conditions, including relaxation delay time, the numbers of scans, and pulse angle, were optimized first. Then method validation was carried out in terms of selectivity, stability, linearity, precision, and robustness. The assay result was compared with that by means of high performance liquid chromatography, which is provided by Chinese Pharmacopoeia. The statistical F test, Student's t test, and nonparametric test at 95% confidence level indicate that there was no significant difference between these two methods. qNMR is a simple and accurate quantitative tool with no need for specific corresponding reference standards. It has the potential of the quantitative analysis of other peptide drugs and standardization of the corresponding reference standards.

Structural Heterogeneities in Solutions of Triethylamine Nitrate Ionic Liquid: 1H NMR and LC Model Study

Zhu Xiao,Zhang Huan,Xu Yingjie

In order to uncover the micro-structural heterogeneities in solutions of ammonium based ionic liquids, triethylamine nitrate (N 222 NO 3 ) has been synthesized using acid–base neutralization and the 1 H NMR spectra of two binary mixtures, namely N 222 NO 3 /dimethyl sulfoxide (DMSO) and N 222 NO 3 /acetone at different concentrations, have been measured at 298.15 K. The internal reference method was adopted to obtain the concentration-dependent chemical shifts of –CH 3 in N 222 NO 3 , which have been correlated using the 1 H NMR local composition (LC) model to obtain the local mole fractions. It has been revealed that within N 222 NO 3 rich region, self-association of the ionic liquid was predominant instead of N 222 NO 3 –solvent interactions. However, in the solvent rich region, N 222 NO 3 mainly interacts with solvent molecules, indicating that the self-association network of N 222 NO 3 has been greatly destroyed by solvents. In addition, the different influences of DMSO and acetone have been detected. DMSO molecules more effectively destroy the original network of the ionic liquid, due to its higher dielectric constant. Also, LC behavior in N 222 NO 3 /DMSO systems is more significant than in N 222 NO 3 /acetone, indicating that DMSO can induce more obvious heterogeneities in DMSO/N 222 NO 3 mixtures, which is consistent with physicochemical properties and cellulose solubility of solutions.

A pH-responsive asymmetric lipid vesicle as drug carrier

Xunan Zhang,Wei Zong,Ying Hu,Nan Luo,Wenlong Cheng,Xiaojun Han

In order to increase the loading efficiency of drug carriers, here we demonstrated a microfluidic method to fabricate an asymmetric vesicle, which contains trichloro(1H,1H,2H,2H-perfluoroocty-l)silane (TPS) inner leaflet and lipid outer leaflet. The asymmetric vesicle was characterised by fluorescence microscopy and Fourier transform infra-red spectrum. In vitro cytotoxicity of the vesicles carrying 5-fluorouacil (5-FU) has also been studied.

Extraction and characterization of Eucommia ulmoides gum from Eucommia leaves by fermentation with Coprinellus disseminatus

Zhang Chuhan,Qin Lijun

AimsTo determine the optimum conditions for extracting Eucommia ulmoides gum (EUG) from Eucommia ulmoides leaves during fermentation by Coprinellus disseminatus. At the same time, the EUG characteristics were characterized.Methods and resultsThe ability of C. disseminatus to secrete degrading enzymes, including enzyme activity and lignocellulose content, was observed by culturing C. disseminatus on a medium with different formulations. Based on the optimal formula, the fermentation conditions were determined by an orthogonal test and EUG was extracted. After that, the characteristic parameters of EUG were determined by FT-IR, 1H-NMR, SEM, POM, DSC, XRD and GPC. The results showed that the lignin and hemicellulose contents in Eucommia leaves decreased significantly with the increase of fermentation days, and C. disseminatus mediated fermentation had an obvious damage effect on the tissue of Eucommia leaves. At the same time, At the same time, xylan can be used as an initiator to induce the expression of degradation-related enzymes. The extraction yield of EUG from Eucommia ulmoides leaves after fermentation was 3.06%, which was significantly improved. The optimum fermentation conditions were 4% inoculum, 28°C fermentation temperature, and pH = 5. The results of infrared FT-IR and 1H-NMR showed that the extract had typical characteristics of EUG, and the surface and quenching part of the EUG were smooth, as observed by SEM. In addition, DSC and XRD analysis show that there are two crystal types, α and β, in the crystallization process of molten EUG. The main crystallization type of EUG extracted from fermented leaves was β type.ConclusionThe ability of C. disseminatus to produce degrading enzymes can effectively improve the extraction rate of EUG under optimal fermentation process. The method can maintain the integrity of gutta-percha better. EUG has the characteristics of good crystallinity, many β crystal types and high molecular weight.

Synthesis and antifungal activity of novel α-alkoxyimino-(1H-benzoimidazol-2-yl)acetonitriles containing piperazine moiety

Jin Qingdong,Li Fubo,Li Ying,Jin Fei,Jiang Lin

A series of α-alkoxyimino-[1-(4-methylpiperazino-1-yl)carbonylmethyl-1 H -benzimidazol-2-yl] acetonitriles were synthesized from o -phenylenediamine, ethyl cyanoacetate, chloroacetyl piperazine, and haloalkane/benzyl chloride by multi-step reactions. The structures of the target compounds were elucidated by IR, 1 H NMR, MS, and elemental analysis. All the target compounds were tested for in vitro antifungal activities against Sclerotinia sclerotiorum and Botrytis cinerea by the mycelium growth rate method, and the results indicated that some compounds displayed higher antifungal activity as compared to carbendazim.

Preparation and Characterization of Attractive Poly(amino acid) Hydrogels Based on 2-Ureido-4[1H]-pyrimidinone

Shi Zhen,Wang Qi,Li Gui-Fei,Shou Yu-Feng,Zong Hong-Jie,Yan Shi-Feng,Zhang Kun-Xi,Yin Jing-Bo

Self-healing hydrogels with the shear-thinning property are novel injectable materials and are superior to traditional injectable hydrogels. The self-healing hydrogels based on 2-ureido-4[1 H ]-pyrimidinone (UPy) have recently received extensive attention due to their dynamic reversibility of UPy dimerization. However, generally, UPy-based self-healing hydrogels exhibit poor stability, cannot degrade in vivo and can hardly be excreted from the body, which considerably limit their bio-application. Here, using poly (l -glutamic acid) (PLGA) as biodegradable matrix, branching α-hydroxy- ω -amino poly(ethylene oxide) (HAPEO) as bridging molecule to introduce UPy, and ethyl acrylate polyethylene glycol (MAPEG) to introduce double bond, the hydrogel precursors (PMHU) are prepared. A library of the self-healing hydrogels has been achieved with well self-healable and shear-thinning properties. With the increase of MAPEG grafting ratio, the storage modulus of the self-healing hydrogels decreases. The self-healing hydrogels are stable in solution only for 6 h, hard to meet the requirements of tissue regeneration. Consequently, ultraviolet (UV) photo-crosslinking is involved to obtain the dual crosslinking hydrogels with enhanced mechanical properties and stability. When MAPEG grafting ratio is 35.5%, the dual crosslinking hydrogels can maintain the shape in phosphate-buffered saline solution (PBS) for at least 8 days. Loading with adipose-derived stem cell spheroids, the self-healing hydrogels are injected and self-heal to a whole, and then they are crosslinked in situ via UV-irradiation, obtaining the dual crosslinking hydrogels/cell spheroids complex with cell viability of 86.7%±6.0%, which demonstrates excellent injectability, subcutaneous gelatinization, and biocompatibility of hydrogels as cell carriers. The novel PMHU hydrogels crosslinked by quadruple hydrogen bonding and then dual photo-crosslinking of double bond are expected to be applied for minimal invasive surgery or therapies in tissue engineering.