Cationic Amphiphilic Model Networks:  Synthesis by Group Transfer Polymerization and Characterization of the Degree of Swelling

2000 ◽  
Vol 33 (8) ◽  
pp. 3176-3179 ◽  
Author(s):  
Martin R. Simmons ◽  
Edna N. Yamasaki ◽  
Costas S. Patrickios
Keyword(s):  
Group Transfer ◽  
Degree Of Swelling ◽  
Model Networks

Randomly cross-linked homopolymer networks: synthesis by group transfer polymerization in solution and characterization of the aqueous degree of swelling

Polymer ◽  
2001 ◽  
Vol 42 (22) ◽  
pp. 9205-9209 ◽  
Author(s):  
Stella C. Hadjiyannakou ◽  
Edna N. Yamasaki ◽  
Costas S. Patrickios
Keyword(s):  
Group Transfer ◽  
Degree Of Swelling

Biopolymers with Medical Applications Optimized method for obtaining chitosan-based delivery systems

2018 ◽  
Vol 69 (7) ◽  
pp. 1756-1759 ◽  
Author(s):  
Luminita Confederat ◽  
Iuliana Motrescu ◽  
Sandra Constantin ◽  
Florentina Lupascu ◽  
Lenuta Profire
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Average Diameter ◽  
Delivery Systems ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Polymeric Systems ◽  
Chitosan Microparticles ◽  
Degree Of Swelling

The aim of this study was to optimize the method used for obtaining microparticles based on chitosan � a biocompatible, biodegradable, and nontoxic polymer, and to characterize the developed systems. Chitosan microparticles, as drug delivery systems were obtained by inotropic gelation method using pentasodiumtripolyphosphate (TPP) as cross-linking agent. Chitosan with low molecular weight (CSLMW) in concentration which ranged between 0.5 and 5 %, was used while the concentration of cross-linking agent ranged between 1 and 5%. The characterization of the microparticles in terms of shape, uniformity and adhesion was performed in solution and dried state. The size of the microparticles and the degree of swelling were also determined. The structure and the morphology of the developed polymeric systems were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The average diameter of the chitosan microparticles was around 522 �m. The most stable microparticles were obtained using CSLMW 1% and TPP 2% or CSLMW 0.75%and TPP 1%. The micropaticles were spherical, uniform and without flattening. Using CSLMW in concentration of 0.5 % poorly cross-linked and crushed microparticles have been obtained at all TPP concentrations. By optimization of the method, stable chitosan-based micropaticles were obtained which will be used to develop controlled release systems for drug delivery.

Synthesis and Characterization of Three-Component Polyelectrolytic Amphiphilic Model Networks

2005 ◽  
Vol 227 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Natalia Hadjiantoniou ◽  
Aggeliki I. Triftaridou ◽  
Theoni K. Georgiou ◽  
Costas S. Patrickios
Keyword(s):  
Synthesis And Characterization ◽  
Model Networks

Characterization of Biomaterials with NMR

1990 ◽  
Vol 217 ◽  
Author(s):  
Leoncio Garrido ◽  
Bettina Pfleiderer ◽  
Jerome L. Ackerman ◽  
John Moore
Keyword(s):  
Chemical Shift ◽  
Mechanical Stress ◽  
Imaging Techniques ◽  
Relaxation Times ◽  
Nmr Imaging ◽  
Spin Lattice ◽  
Model Networks ◽  
Crosslink Densities

ABSTRACTSilicone based biomaterials are characterized with NMR. Bulk spin-lattice (T1) and spin-spin (T2) relaxation times are measured in polydimethylsiloxane (PDMS) model networks and various types of implants. The T2 results seem to indicate that crosslink densities of these biomaterials are lower than those of the PDMS model networks studied. 1H chemical shift NMR imaging techniques are developed to investigate the aging (e.g., migration of free polymer, rupture due to mechanical stress, etc.) of biomaterials in vivo.

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