scholarly journals The Physico-Chemical Properties of Glipizide: New Findings

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3142
Author(s):  
Giovanna Bruni ◽  
Ines Ghione ◽  
Vittorio Berbenni ◽  
Andrea Cardini ◽  
Doretta Capsoni ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Analytical Techniques ◽  
Kinetic Studies ◽  
Polymorphic Form ◽  
Decomposition Process ◽  
Endothermic Peak ◽  
Physico Chemical ◽  
New Findings ◽  
Chemical Studies ◽  
Ft Ir

The present work is a concrete example of how physico-chemical studies, if performed in depth, are crucial to understand the behavior of pharmaceutical solids and constitute a solid basis for the control of the reproducibility of the industrial batches. In particular, a deep study of the thermal behavior of glipizide, a hypoglycemic drug, was carried out with the aim of clarifying whether the recognition of its polymorphic forms can really be done on the basis of the endothermic peak that the literature studies attribute to the melting of the compound. A number of analytical techniques were used: thermal techniques (DSC, TGA), X-ray powder diffraction (XRPD), FT-IR spectroscopy and scanning electron microscopy (SEM). Great attention was paid to the experimental design and to the interpretation of the combined results obtained by all these techniques. We proved that the attribution of the endothermic peak shown by glipizide to its melting was actually wrong. The DSC peak is no doubt triggered by a decomposition process that involves gas evolution (cyclohexanamine and carbon dioxide) and formation of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which remains as decomposition residue. Thermal treatments properly designed and the combined use of DSC with FT-IR and XRPD led to identifying a new polymorphic form of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which is obtained by crystallization from the melt. Hence, our results put into evidence that the check of the polymorphic form of glipizide cannot be based on the temperature values of the DSC peak, since such a peak is due to a decomposition process whose Tonset value is strongly affected by the particle size. Kinetic studies of the decomposition process show the high stability of solid glipizide at room temperature.

scholarly journals Exploring the difference in xerogels and organogels through in situ observation

2018 ◽  
Vol 5 (1) ◽  
pp. 170492
Author(s):  
Binglian Bai ◽  
Zhiming Li ◽  
Haitao Wang ◽  
Min Li ◽  
Yukihiro Ozaki ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Fluorescence Spectra ◽  
Chemical Properties ◽  
Columnar Structure ◽  
In Situ Observation ◽  
Physico Chemical ◽  
Aggregation Structure ◽  
Ft Ir ◽  
The Difference

Solvent–gelator interactions play a key role in mediating organogel formation and ultimately determine the physico-chemical properties of the organogels and xerogels. The ethanol organogels of 1,4-bis[(3,4,5-trihexyloxy phenyl)hydrazide]phenylene (TC6) were investigated in situ by FT-IR, Raman and fluorescence spectra, and XRD, and it was confirmed that the intermolecular interaction and aggregation structure of TC6 ethanol organogels were quite different from those of xerogels. Simultaneously, unprecedented phase transition from organogel to suspension upon heating was observed in ethanol organogel, and the suspension phase exhibited lytropic liquid crystalline behaviour with a rectangular columnar structure. This study may open the possibility to design new gelators with a new dimension of versatility.

Characterization of Spent Catalysts during Hydrodemetallization of Atmosphere Residue

2011 ◽  
Vol 236-238 ◽  
pp. 538-542
Author(s):  
Yong Jun Liu
Keyword(s):  
Chemical Properties ◽  
Analytical Techniques ◽  
Resonance Spectroscopy ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Spent Catalysts ◽  
C Nmr

The deactivation behavior of industrial hydrodemetallization catalysts was investigated in the presented work. The main objective of the study is to contribute to a better understanding of the nature of the coke and metal deposition on the used catalysts by applying chemical analysis and various advanced analytical techniques, such as X-ray diffraction analysis (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and solid-state carbon-13 nuclear magnetic resonance spectroscopy (13C NMR). The results are discussed scientifically based on the physico–chemical properties of origin and used catalysts.

Autoclave-assisted green synthesis of silver nanoparticles using A. fumigatus mycelia extract and the evaluation of their physico-chemical properties and antibacterial activity

2018 ◽  
Vol 7 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Sarah Ghanbari ◽  
Hamideh Vaghari ◽  
Zahra Sayyar ◽  
Mohammad Adibpour ◽  
Hoda Jafarizadeh-Malmiri
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Chemical Properties ◽  
Heating Time ◽  
Gram Negative Bacteria ◽  
Synthesis Conditions ◽  
High Antibacterial Activity ◽  
Physico Chemical ◽  
Ft Ir

Abstract Silver nanoparticles (AgNPs) were synthesized using Aspergillus fumigatus (A. fumigatus) mycelia extract via the hydrothermal method. The main reducing and stabilizing groups and components of A. fumigatus extract, such as amine, hydroxyl, amid, protein, enzymes, and cell saccharide compounds, were identified by Fourier transform infrared (FT-IR). Central composition design was used to plan the experiments, and response surface methodology was applied to evaluate of the effects of independent variables, including the amount of the prepared extract (5–7 ml) and heating time (10–20 min) at 121°C and 1.5 bar), on the particle size of the synthesized AgNPs, as manifested in broad emission peak (λmax). More stable and spherical monodispersed AgNPs, with mean particle size, polydispersity index (PDI) value, and maximum ζ potential value of 23 nm, 0.270, and +35.3 mV, respectively, were obtained at the optimal synthesis conditions using 7 ml of A. fumigatus extract and heating time of 20 min. The synthesized AgNPs indicated high antibacterial activity against both Gram-positive and Gram-negative bacteria.

scholarly journals Preparation and of PVA-based compositions with embedded silver, copper and zinc oxide nanoparticles and assessment of their antibacterial properties

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Jolanta Pulit-Prociak ◽  
Anita Staroń ◽  
Paweł Staroń ◽  
Anna Chmielowiec-Korzeniowska ◽  
Agata Drabik ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Metallic Nanoparticles ◽  
Antibacterial Properties ◽  
Chemical Properties ◽  
Microscopic Analysis ◽  
Poly Vinyl Alcohol ◽  
Physico Chemical ◽  
Dynamic Light Scattering Technique ◽  
Ft Ir ◽  
Bacterial Film

Abstract A series of poly(vinyl alcohol) (PVA) based liquid compositions with addition of zinc oxide, silver and copper nanoparticles has been prepared. The compositions also contained other consistency-forming organic components. The physico-chemical properties of the products have been determined. Their pH and density have been assessed. Also, the size of nanoparticles has been defined with using a dynamic light scattering technique. The compositions were subjected to XRD, FT-IR and microscopic analysis as well. Thanks to the incorporation of both metal oxide and metallic nanoparticles, it was possible to enrich the products with antibacterial properties. Their inhibiting properties in the growth of microorganisms have been confirmed against both Gram-negative and Gram-positive strains such as E. coli, S. aureus and P. aeruginosa. Thanks to the ability for solidification, the compositions may be applied on a bacterially contaminated surface, and after destroying the microorganisms and its solidification, it may be peeled off along with the dead bacterial film.

Structural and Photocatalytic Property of CaTiO3 Nanosphere

2020 ◽  
Vol 979 ◽  
pp. 169-174 ◽  
Author(s):  
C. Karthikeyan ◽  
M. Thamima ◽  
S. Karuppuchamy
Keyword(s):  
Dye Degradation ◽  
Uv Light ◽  
Chemical Properties ◽  
Photocatalytic Property ◽  
Advanced Characterization ◽  
Morphological Studies ◽  
Physico Chemical ◽  
Raman Study ◽  
Ft Ir ◽  
Xrd Patterns

The nanostructured photocatalysts are the most promising materials for the degradation of toxic dyes. Particularly, CaTiO3 has been used in several applications including catalytic, optical, biological and electronic. In this present study, perovskite structured CaTiO3 nanomaterials have been synthesized by microwave irradiation method. The physico-chemical properties of the prepared CaTiO3 nanomaterials were studied by various advanced characterization techniques. The XRD patterns confirm the presence of perovskite structure of the prepared nanomaterials. FT-IR analysis confirms the presence of Ca-Ti-O vibrational bonds. Micro Raman study display the existence of O-Ca-Ti-O with B1g mode of vibrations. Morphological studies revealed the presence of truncated nanospheres. The dye degradation property of prepared CaTiO3 was investigated by Malachite green (MG) by UV-light.

scholarly journals Chemical characterization of laboratory-generated tar ball particles

2018 ◽  
Author(s):  
Ádám Tóth ◽  
András Hoffer ◽  
Mihály Pósfai ◽  
Tibor Ajtai ◽  
Zoltán Kónya ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Total Carbon ◽  
Total Carbon Content ◽  
Molar Ratios ◽  
Carbon Structures ◽  
Sampling Campaign ◽  
Ft Ir ◽  
Heterocyclic Aromatics

Abstract. The chemical properties of tar ball (TB) particles generated from dry distillate (wood tars) of three different wood species in the laboratory were investigated by analytical techniques that had never been used before, for their characterization. The elemental composition of TB particles from three tree species were very similar to one another and to those characteristic for atmospheric tar balls (TBs) collected from savanna fire during the SAFARI 2000 sampling campaign. The O / C and H / C molar ratios of the generated TBs were at the upper limit characteristic for soot particles. The FT-IR spectra of the generated TBs were very similar to one another as well and also showed some similarity with those of atmospheric humic-like substances (HULIS). The FT-IR measurements indicated that laboratory-generated TBs have a higher proportion of aromatic structure than HULIS and the oxygen atoms of TBs are mainly found in hydroxyl and keto functional groups. Whereas the starting materials of the TBs (wood tars) were Raman inactive in the range of 1000–1800 cm−1, the Raman spectra of TBs were dominated by two pronounced bands with intensity maxima near 1580 (G band) and 1350 cm−1 (D band), indicating the presence of sp2-hybridised carbon structures and disorder in them, respectively. In the Py-GC-MS chromatograms of the laboratory-generated TBs mostly aromatic compounds (aromatic hydrocarbons, oxygenated aromatics and heterocyclic aromatics) were identified in accordance with the results of Raman and FT-IR spectroscopy. According to OC / EC analysis using EUSAAR_2 long thermal protocol, 22 % of the total carbon content of laboratory-generated TBs was identified as elemental carbon (EC), contrary to expectations based on the current understanding that negligible if any EC is present in this sub-fraction of the brown carbon family. Our results suggest that spherical atmospheric TBs with high C / O molar ratios are closer to BC in many of their properties than to weakly absorbing HULIS.

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