Search results

1

Interaction of anesthetic supplement thiopental with human serum albumin

100%

Khan S., Islam B., Rajeswari M., Usmani, H., Khan A.

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2008

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vol. 55

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issue 2

399-409

EN

Thiopental (TPL) is a commonly used barbiturate anesthetic. Its binding with human serum albumin (HSA) was studied to explore the anesthetic-induced protein dysfunction. The basic binding interaction was studied by UV-absorption and fluorescence spectroscopy. An increase in the binding affinity (K) and in the number of binding sites (n) with the increasing albumin concentration was observed. The interaction was conformation-dependent and the highest for the F isomer of HSA, which implicates its slow elimination. The mode of binding was characterized using various thermodynamic parameters. Domain II of HSA was found to possess a high affinity binding site for TPL. The effect of micro-metal ions on the binding affinity was also investigated. The molecular distance, r, between donor (HSA) and acceptor (TPL) was estimated by fluorescence resonance energy transfer (FRET). Correlation between the stability of the TPL-N and TPL-F complexes and drug distribution is discussed. The structural changes in the protein investigated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy reflect perturbation of the albumin molecule and provide an explanation for the heterogeneity of action of this anesthetic.

2

Vibrational Spectroscopic and Computational Studies on Bis(2-aminopyridinium)fumarate - Fumaric Acid (1:1) Complex

100%

Kanagathara N., Pawlus K., Marchewka M.

Acta Physica Polonica A

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2018

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vol. 133

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issue 1

45-56

EN

The new vibrational and computational studies on bis(2-aminopiridinium) fumarate - fumaric acid (1:1) complex have been made. The molecular geometry, vibrational frequencies and intensities of vibrational bands have been interpreted with the aid of structure optimization based on density functional theory (B3LYP) method with 6-311++G(d,p) basis set. The highly occupied-lowly unoccupied molecular orbital energies and chemical reactivity of the molecule have been calculated with time-dependent density functional theory approach. Stability energies of the molecule have been studied using natural bond orbital analysis. The predicted nonlinear optical properties of the title compound are much greater that those of urea. In addition, the molecular electrostatic potential surfaces and thermodynamic properties were calculated.

3

THE POSSIBILITY OF USING X-RAY POWDER DIFFRACTION, INFRARED AND RAMAN SPECTROSCOPY IN THE STUDY OF THE IDENTIFICATION OF STRUCTURAL POLYMORPHS OF ACETAMINOPHEN

100%

Stasiłowicz A., Mizera M., Tykarska E., Lewandowska K., Miklaszewski A., Cielecka-Piontek J.

Acta Poloniae Pharmaceutica - Drug Research

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2019

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vol. 76

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issue 6

997-1004

EN

Paracetamol (acetaminophen), a pain-killer with antipyretic properties, shows structural polymorphism. It occurs in three polymorphic forms: monoclinic, orthorhombic, and unstable form III. In the study, the commercially available samples of paracetamol (P1 and P2) were examined using X-ray powder diffraction, infrared, and Raman spectroscopy. Results demonstrated that all of the methods defined polymorphic forms of paracetamol in the samples. However, only Raman spectroscopy and PXRD methods detected impurities in the sample P1. These methods transpired to be more sensitive than the FT-IR method, which identified samples of paracetamol as one structural form (monoclinic polymorph). Moreover, the Raman spectroscopy identified impurities in the form P1 as changes in the crystalline form.

4

Scaled quantum chemical studies of the structural and vibrational spectra of acetyl coumarin

100%

Bahgat K.

Open Chemistry

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2006

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vol. 4

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issue 4

773-785

EN

The solid phase FT-IR and FR-Raman spectra of acetyl coumarin have been recorded in the regions 4000–50 cm−1. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on density functional theory (DFT) and Hartree-Fock (HF) at 6–31G* and 6–311++G** basis sets. The resulting force fields were transformed to internal coordinates, the calculated vibrational frequencies and normal modes were utilized in the assignment of the observed vibrational fundamentals. The measured spectral data were used to refine the vibrational force constants by means of a small number of scaling factors.

5

The effect of supports on coke deposition on supported platinum and platinum-tin catalysts investigated by FT-IR spectroscopy

86%

Sarbak Z.

Polish Journal of Chemical Technology

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2007

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vol. 9

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issue 1

23-26

EN

Coke deposit is produced from ethylene on the surface of the platinum and platinum-tin catalysts supported on two various Al2 O3, SiO2 and SiO2 -Al2O3. The coke amount and the structure depend on the type and the amount of the components introduced onto the catalyst support and on the type of the support. It has been found that the surface area of the support has no significant effect on the type of species in the coke deposit. The analysis of the FT-IR spectra has shown the presence of different species on the surface of the catalysts, including carboxyl groups, pseudo-graphite (polyaromatic) structures, polyphenylene groups, acetyl groups, carbonyl groups of acetone and formate type, enol species.

6

SYNTHESIS OF NEW CHITOSAN-CARBONATE HYDROXYAPATITE COMPOSITES WITH POTENTIAL APPLICATION IN BONE TISSUE ENGINEERING – PHYSICOCHEMICAL ANALYSIS

86%

Urbaniak J., Kołodziejska B., Kaflak A.

Progress on Chemistry and Application of Chitin and its Derivatives

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2022

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vol. 27

217-227

EN

The subject of this study was the synthesis of 12 chitosan-hydroxyapatite (CH:HA) composites with different contents of carbonate ions (CO3 2-), in two weight ratios of CH to HA (30:70 and 50:50), and two viscosities of CH (low [L] and high [H]). The method of direct co-precipitation of the introduced reagents was used. The structure of the obtained materials was characterised by Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction, and scanning electron microscopy. The FT-IR spectra revealed the bands and ranges of the characteristic bands for CH and HA. The presence of CO3 2- introduced into the structure of the obtained composites was identified by infrared spectroscopy. A reduction in the size of HA unit cells was observed in the obtained CH:HA biocomposites, in materials with a higher content of incorporated CO3 2-. The obtained nanomaterials are similar to natural bone tissue. Future research will focus on the evaluation of the obtained materials as a drug delivery system.

7

The radiolytic studies of panipenem in the solid state

86%

Zalewski P., Rosiak N., Kilińska K., Skibiński R., Szymanowska D., Tykarska E., Piekara-Sady L., Lewandowska K., Miklaszewski A., Piontek J. C.

Acta Poloniae Pharmaceutica - Drug Research

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2020

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vol. 77

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issue 2

241-250

EN

The influence of ionizing radiation on the physicochemical properties of panipenem in solid state was studied. In the first part of our studies, we evaluated the possibility of applying radiosterilization to obtain sterile panipenem. Spectroscopic (FT-IR, Raman), chromatography (HPLC and HPLC-MS) and X-ray powder diffraction (XRPD) studies have shown that irradiation of ertapenem with the 25 kGy, the dose required to achieve sterility, does not change the physicochemical properties of the studied compound. The antimicrobial activity of panipenem irradiated with the dose of 25 kGy was reduced for three species. It was confirmed that the decrease in antimicrobial activity might be related to isomerization of panipenem.

Refine search results

Interaction of anesthetic supplement thiopental with human serum albumin

Vibrational Spectroscopic and Computational Studies on Bis(2-aminopyridinium)fumarate - Fumaric Acid (1:1) Complex

THE POSSIBILITY OF USING X-RAY POWDER DIFFRACTION, INFRARED AND RAMAN SPECTROSCOPY IN THE STUDY OF THE IDENTIFICATION OF STRUCTURAL POLYMORPHS OF ACETAMINOPHEN

Scaled quantum chemical studies of the structural and vibrational spectra of acetyl coumarin

The effect of supports on coke deposition on supported platinum and platinum-tin catalysts investigated by FT-IR spectroscopy

SYNTHESIS OF NEW CHITOSAN-CARBONATE HYDROXYAPATITE COMPOSITES WITH POTENTIAL APPLICATION IN BONE TISSUE ENGINEERING – PHYSICOCHEMICAL ANALYSIS

The radiolytic studies of panipenem in the solid state