scholarly journals Understanding the structure and dynamics of anti-inflammatory corticosteroid dexamethasone by solid state NMR spectroscopy

RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37564-37575
Author(s):  
Krishna Kishor Dey ◽  
Manasi Ghosh
Keyword(s):  
Relaxation Time ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Site Specific ◽  
Spin Lattice ◽  
Structure And Dynamics

The structure and dynamics of dexamethasone is determined by measuring CSA tensor, site-specific spin–lattice relaxation time.

Determination of the correlation between the structure and dynamics of deflazacort by solid state NMR measurements

2020 ◽  
Vol 44 (42) ◽  
pp. 18419-18430 ◽  
Author(s):  
Krishna Kishor Dey ◽  
Manasi Ghosh
Keyword(s):  
Relaxation Time ◽  
Solid State ◽  
Solid State Nmr ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Structure And Dynamics

The correlation between the structure and dynamics of glucocorticoid deflazacort is determined by a 2DPASS CP-MAS SSNMR experiment and 13C spin–lattice relaxation time by a Torchia CP experiment.

The Use of Solid State NMR to Evaluate EVA/Silica FILMs

2012 ◽  
Vol 18-19 ◽  
pp. 219-226 ◽  
Author(s):  
Adriano Alves Passos ◽  
Maria Inês Bruno Tavares ◽  
Roberto Cucinelli P. Neto ◽  
Antonio G. Ferreira
Keyword(s):  
Relaxation Time ◽  
Solid State ◽  
Solid State Nmr ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Silica Oxide

Nanocomposites based on ethylene-co-vinyl acetate (EVA) and silica oxide (SiO2), with nanometric size (40nm) were prepared by solution process, employing chloroform as solvent. The nanocomposites were mainly characterized by solid state nuclear magnetic resonance spectroscopy (NMR). From the methodology employed polymer matrix was evaluated by the determination of proton nuclear spin-lattice relaxation time (T1H) and spin-spin relaxation time (T2H) employing low field NMR spectrometer and also applying carbon-13 (13C) solid-state NMR techniques and proton spin-lattice relaxation time in the rotating frame (T1pH) by high field NMR. The nanoparticle, silica oxide, was analyzed by silicon-29 (29Si) NMR MAS spectrum. The evaluation of relaxation time showed an increase in the proton spin-lattice relaxation time, because of silicon nucleus interaction with polymer chains promoting an increase in the sample rigidity, which is a result of good silica oxide dispersion in the polymeric matrix. The nanomaterial with 5% of SiO2presented good dispersion of silica oxide in the polymeric matrix, because of the formation of strong intermolecular interaction.

scholarly journals Study the Structure and Dynamics of Antifungal Agent Ketoconazole by CSA and Site-Specific Spin-Lattice Relaxation Time Measurements

2021 ◽  
Author(s):  
Krishna Kishor Dey ◽  
Manasi Ghosh
Keyword(s):  
Relaxation Time ◽  
Correlation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Site Specific ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Structure And Dynamics ◽  
Molecular Correlation

Abstract An azole antifungal agent, ketoconazole, is widely used in the treatment of mucosal fungal infections related to AIDS immunosuppression, organ transplantation, and cancer chemotherapy. The structure and dynamics of ketoconazole are thoroughly studied by chemical shift anisotropy tensor and site-specific spin-lattice relaxation time measurements. The molecular correlation time at crystallographically different carbon sites is calculated by considering that the spin-lattice relaxation mechanism for the 13C nucleus is mainly governed by chemical shift anisotropy interaction and hetero-nuclear dipole-dipole coupling. The CSA parameters at the crystallographically distinct sites of ketoconazole are determined by two-dimensional phase adjusted spinning sideband (2D PASS) cross-polarization magic angle spinning (CP-MAS) solid-state NMR experiment. The site-specific spin-lattice relaxation time is measured by the Torchia CP experiment. The spin-lattice relaxation rate is slow for all the carbon nuclei sites except C2, C3, C4, C5, and C26 carbon nuclei reside on the piperazine ring and the methyl group. It suggests the close-pack arrangement of the molecule due to π-π stacking interaction. The molecular correlation time of all the carbon atoms reside on the benzene ring, 1,3-dioxolane ring, imidazole ring, and the 2,4-dichlorobenzene ring is of the order of 10-4 s, while it is of the order of 10-7 s for carbon atoms reside on the piperazine ring. The CSA parameters of the carbon nuclei on the piperazine ring (C2, C3, C4, C5), and the methyl group (C26) are very low compared to other carbon nuclei. The CSA parameters are very high for carbon nuclei reside on the benzene ring, imidazole ring, and the 2,4-dichlorobenzene ring due to the presence of π-electrons. A huge variation of the spin-lattice relaxation time and the molecular correlation time are observed for numerous carbon nuclei situated on the side-chain of ketoconazole. The spin-lattice relaxation time varies from 500 s to 8 s, and the molecular correlation time varies in the range of 10-4s to 10-7s. These types of investigations portrayed the correlation between the structure and dynamics of the antifungal drug ketoconazole, which will help to develop the advanced antifungal drugs. Additionally, the CSA information of the drug molecules will be immensely useful for NMR crystallography.

scholarly journals An atomic resolution description of folic acid using solid state NMR measurements

RSC Advances ◽  
2020 ◽  
Vol 10 (42) ◽  
pp. 24973-24984 ◽  
Author(s):  
Manasi Ghosh ◽  
Shovanlal Gayen ◽  
Krishna Kishor Dey
Keyword(s):  
Folic Acid ◽  
Solid State Nmr ◽  
Chemical Shift Anisotropy ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Site Specific ◽  
Spin Lattice ◽  
Anisotropy Tensor ◽  
Cp Mas Nmr

The chemical shift anisotropy tensor and site specific spin-lattice relaxation time of folic acid were determined by a 13C 2DPASS CP-MAS NMR experiment and Torchia CP experiment respectively.

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