13C Solid-State NMR Determination of Cross-Linking Degree in Superabsorbing Cellulose-Based Networks

2000 ◽  
Vol 33 (2) ◽  
pp. 430-437 ◽  
Author(s):  
Donatella Capitani ◽  
Matteo Alessandro Del Nobile ◽  
Giuseppe Mensitieri ◽  
Alessandro Sannino ◽  
Anna Laura Segre
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Cross Linking

Development and Characterization of LBG-PVA Interpenetrating Networks Incorporating Gliclazide for Sustained Release

2020 ◽  
Vol 15 ◽  
Author(s):  
Ashish Katoch ◽  
Manju Nagpal ◽  
Malkiet Kaur ◽  
Manjinder Singh ◽  
Geeta Aggarwal ◽  
...  
Keyword(s):  
Solid State ◽  
Sustained Release ◽  
Half Life ◽  
Solid State Nmr ◽  
Oral Dosage ◽  
Cross Linking ◽  
Interpenetrating Networks ◽  
Dsc Studies ◽  
Biological Half Life ◽  
Percentage Yield

Background: Controlled oral dosage forms have always been preferred for drugs with variable absorption, and short biological half life and frequent dosing. The prime goal with sustained release systems is to maintain uniform therapeutic blood levels for longer periods of time. Interpenetrating networks (IPNs) have been evidenced as uniform sustained release systems. In current study, polyvinyl alcohol (PVA) and locust bean gum (LBG) based IPNs were developed for the oral sustained release drug delivery of gliclazide (shows variable absorption). Method: The IPNs were synthesized by emulsion cross-linking method using glutaraldehyde (GA) as a cross linking agent. Gliclazide is a potential second generation, short-acting sulfonylurea oral hypoglycemic agent is having a short biological half-life (2-4 h), variable absorption and poor oral bioavailability. Various batches of IPNs were formulated by varying LBG: PVA ratio and evaluated for percentage yield, drug entrapment efficiency (DEE), swelling properties and in vitro drug release studies. Further characterizations were done by Fourier Transform Infrared Spectroscopy (FTIR), C13 Solid state NMR, X-Ray diffraction study (XRD), Scanning electron microscopy (SEM), and Differential scanning microscopy (DSC) studies. Results: The percentage yield, drug entrapment and equilibrium swelling was observed to be dependent on PVA-LBG ratio and GA amount. Sustained release of drug was observed in all IPN formulations (approx 59 - 86% in 8 h in various batches) with variable release kinetics. SEM studies revealed the regular structures of IPNs. FTIR, XRD, C13 Solid state NMR and DSC studies proposed that drug was successfully incorporated into the formed IPNs. Conclusion: IPNs of LBG and PVA can be used as a promising carrier with uniform sustained release characteristics.

scholarly journals Structure determination of molecular nanocomposites by combining pair distribution function analysis and solid-state NMR

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 8895-8902 ◽  
Author(s):  
E.-E. Bendeif ◽  
A. Gansmuller ◽  
K.-Y. Hsieh ◽  
S. Pillet ◽  
Th. Woike ◽  
...  
Keyword(s):  
Distribution Function ◽  
Solid State ◽  
Solid State Nmr ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Structural Characterisation ◽  
Atomic Pair Distribution Function ◽  
X Ray Scattering ◽  
Atomic Pair

Total X-ray scattering coupled to atomic pair distribution function analysis (PDF) and solid state NMR allowed the identification and structural characterisation of isolated molecules and nanocrystals of sodium nitroprusside confined in mesoporous silica.

Solid-State NMR Structure Determination of Whole Anchoring Threads from the Blue Mussel Mytilus edulis

2012 ◽  
Vol 14 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Alexandre A. Arnold ◽  
Frédéric Byette ◽  
Marc-Olivier Séguin-Heine ◽  
André LeBlanc ◽  
Lekha Sleno ◽  
...  
Keyword(s):  
Solid State ◽  
Mytilus Edulis ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Blue Mussel ◽  
Nmr Structure ◽  
Nmr Structure Determination

scholarly journals Multidimensional high-resolution solid-state NMR for the structure determination of ^C/^N-labeled biomolecules

2000 ◽  
Vol 40 (supplement) ◽  
pp. S174
Author(s):  
Y. Todokoro ◽  
H. Yanagishita ◽  
T. Fujiwara ◽  
H. Akutsu
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Structure Determination ◽  
Solid State Nmr

Determination of the charge of Al13 Keggin oligocations intercalated into synthetic hectorite

2019 ◽  
Vol 74 (1) ◽  
pp. 85-90
Author(s):  
Marius Schöttle ◽  
Dominik Schuchardt ◽  
Andreas Edenharter ◽  
Sebastian Koch ◽  
Jürgen Senker ◽  
...  
Keyword(s):  
Reaction Time ◽  
Solid State ◽  
Ir Spectroscopy ◽  
Cation Exchange ◽  
Elemental Analysis ◽  
Crystalline Phase ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
A Charge

AbstractApplying a nematic liquid crystalline phase of a synthetic Na-hectorite with layer separations >100 nm, the reaction time for pillaring with Al13 Keggin oligocation could be reduced to seconds ensuring that cation exchange is controlled by thermodynamics. With this material at hand we are able to resolve the long-standing dispute regarding the charge of intercalated Keggin oligocations. Micropore sizes as determined by physisorption isotherms, adsorption isotherms obtained via elemental analysis, and results of 27Al solid-state NMR and pyridine probe IR spectroscopy favor a charge of +7 for the Al13 pillars intercalated into hectorite unaltered.

Solid-state NMR at natural isotopic abundance for the determination of conformational polymorphism – the case of designed β-turn peptides containing di-prolines

2017 ◽  
Vol 53 (7) ◽  
pp. 1317-1320 ◽  
Author(s):  
Jayasubba Reddy Yarava ◽  
Rajesh Sonti ◽  
K. Kantharaju ◽  
S. Raghothama ◽  
K. V. Ramanathan
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Solution Nmr ◽  
Isotopic Abundance ◽  
Conformational Polymorphism ◽  
Natural Isotopic Abundance

Like nOe in solution NMR, through-space proton correlations have been exploited in the solid state to obtain the cis–trans conformational polymorphism.

scholarly journals 3D structure determination of amyloid fibrils using solid-state NMR spectroscopy

Methods ◽  
2018 ◽  
Vol 138-139 ◽  
pp. 26-38 ◽  
Author(s):  
Antoine Loquet ◽  
Nadia El Mammeri ◽  
Jan Stanek ◽  
Mélanie Berbon ◽  
Benjamin Bardiaux ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Amyloid Fibrils ◽  
3D Structure ◽  
Solid State Nmr Spectroscopy ◽  
3D Structure Determination

Determination of methyl order parameters using solid state NMR under off magic angle spinning

2019 ◽  
Vol 73 (8-9) ◽  
pp. 471-475 ◽  
Author(s):  
Kai Xue ◽  
Salvatore Mamone ◽  
Benita Koch ◽  
Riddhiman Sarkar ◽  
Bernd Reif
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Order Parameters ◽  
Magic Angle ◽  
Angle Spinning

Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations

2018 ◽  
Vol 109 ◽  
pp. 51-78 ◽  
Author(s):  
Jean-Philippe Demers ◽  
Pascal Fricke ◽  
Chaowei Shi ◽  
Veniamin Chevelkov ◽  
Adam Lange
Keyword(s):  
Solid State ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Molecular Assemblies
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