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Xue-jie Wang

Bio: Xue-jie Wang is an academic researcher from Zhejiang International Studies University. The author has contributed to research in topics: Thermal decomposition & Decomposition. The author has an hindex of 4, co-authored 7 publications receiving 32 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the thermal decomposition of a nucleoside drug, namely, Gemcitabine (GTB), was investigated using the ATSM method, and the results indicated that two strong electronegative fluorine atoms on furan ring make the strong charge transfer (CT) structure to be formed, this strong CT structure remarkably enhance the N-glycosidic bond and the weakest bond, and lead to higher thermal stability and distinctive thermal decomposition mechanism.

10 citations

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TL;DR: In this article, thermal decomposition processes of TDF were measured with thermogravimetry, differential scanning calorimetry and thermal gating analysis coupled with Fourier transform infrared spectroscopy, and molecular bond orders were calculated using an ab initio method from the GAMESS program of quantum chemistry.
Abstract: Tenofovir disoproxil fumarate (TDF) is an antiretroviral medication widely used to prevent and treat HIV/AIDS and to treat chronic hepatitis B. In this paper, thermal decomposition processes of TDF were measured with thermogravimetry, differential scanning calorimetry and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The IR spectra, high-performance liquid chromatography and liquid chromatography mass spectrometry of TDF and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated using an ab initio method from the GAMESS program of quantum chemistry. The mechanism of thermal decomposition was discussed. The results indicated that the thermal decomposition of TDF is a three-step process, the initial step of thermal decomposition of TDF is the decomposition of carboxylic ester, the first stage mainly is the decomposition of the phosphoric disoproxil section, and the second stage mainly is the decomposition of the tenofovir section and partially goes through adenine stage. The initial decomposition temperature in either nitrogen or air is 138 °C, and the thermal stability of TDF is not very good under routine temperature.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the molecular bond orders of purine nucleoside analogs were calculated with an ab initio method from the GAMESS program, which can serve as the basis to judge molecular thermal stability for analog compounds with similar molecular structure and energy.

7 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the thermal decomposition of sofosbuvir (SOF) with thermogravimetric, differential scanning calorimetry, and thermal analysis coupled with Fourier transform infrared spectroscopy.

6 citations

Journal ArticleDOI
TL;DR: In this article, the thermal decomposition of Tenoxicam (TNX) was investigated with thermogravimetry and differential thermal analysis. And the potential lifetime of tenoxicam was estimated using the ATSM E1877 method.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a review of recent analytical applications of evolved gas analysis performed by infrared spectroscopy (EGA-IR), selected among those published in the years 2013 to 2015, are collected.
Abstract: Several analytical instruments (like pyrolyzers, thermobalances, differential thermal analyzers, or calorimeters, and sometimes simply temperature-controlled reactors) can be on-line coupled to infrared spectrometers to perform evolved gas analysis (EGA). Advances in EGA techniques are currently proposed by the scientific literature because the possibility to on-line detect the nature of the released gases or vapors has become fundamental to proving a supposed reaction, either under isothermal or under heating conditions. In this review, recent analytical applications of evolved gas analysis performed by infrared spectroscopy (EGA-IR), selected among those published in the years 2013 to 2015, are collected.

53 citations

Journal ArticleDOI
Furong Hou1, Xiaobin Ma1, Lihua Fan1, Danli Wang1, Tian Ding1, Xingqian Ye1, Donghong Liu1 
TL;DR: Combination of chitinase and ultrasound could enhance the hydrolysis of CS while without changing its primary structure, according to degradation kinetics and structural characteristics.

31 citations

Journal ArticleDOI
TL;DR: Through this study, it was possible to establish the most suitable crystalline form of sitagliptin for the development of a safe, effective and appropriate pharmaceutical dosage form.
Abstract: Sitagliptin is an inhibitor of the enzyme dipeptidyl peptidase-4, used for the treatment of type 2 diabetes mellitus. The crystal structure of active pharmaceutical solids determines their physical and chemical properties. The polymorphism, solvates and hydrates can influence the free energy, thermodynamic parameters, solubility, solid-state stability, processability and dissolution rate, besides directly affecting the bioavailability. Thus, the physicochemical characterization of an active pharmaceutical ingredient is required to guarantee the rational development of new dosage forms. In this context, we describe herein the solid-state characterization of three crystalline forms of sitagliptin: sitagliptin phosphate monohydrate, sitagliptin phosphate anhydrous and sitagliptin base form. The investigation was carried out using differential scanning calorimetry (DSC), thermogravimetry (TG)/derivative thermogravimetry (DTG), spectroscopic techniques, X-ray powder diffraction (XRPD) and morphological analysis by scanning electron microscopy. The thermal analysis revealed that during the dehydration of sitagliptin phosphate monohydrate (Tpeak = 134.43 °C, ΔH = −1.15 J g−1) there is a characteristic crystalline transition event, which alters the physicochemical parameters of the drug, such as the melting point and solubility. The crystalline behavior of sitagliptin base form differs from that of sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous, mainly with regard to the lower temperature of the fusion event. The melting point (Tpeak) values obtained were 120.29 °C for sitagliptin base form, 206.37 °C for sitagliptin phosphate monohydrate and 214.92 °C for sitagliptin phosphate anhydrous. In relation to the thermal stability, sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous showed a slight difference; however, both are more thermostable than the base molecule. Therefore, through this study it was possible to establish the most suitable crystalline form of sitagliptin for the development of a safe, effective and appropriate pharmaceutical dosage form.

27 citations

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TL;DR: In this article, the synthesis of amino-decorated mesoporous silica nanoparticles (MSNs) for sustained delivery and enhanced bioavailability of sofosbuvir was described.

25 citations

Journal ArticleDOI
TL;DR: The described SERS purine-nanomat substrate enables the detection of uric acid, an important indicator of gout, preeclampsia, cardiovascular and kidney diseases, in aqueous solution up to 100 nM, with good stability and high sensitivity, offering superiority over existing techniques in terms of sensitivity and cost-effectiveness.

18 citations