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Drug Diffusion in Neutral and Ionic Hydrogels Assembled from Acetylated Galactoglucomannan
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
Show others and affiliations
2009 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 112, no 4, 2401-2412 p.Article in journal (Refereed) Published
Abstract [en]

In this study, hydrogels based on acetylated galactoglucomannan (AcGGM)-a hemicellulose present in softwood-were synthesized and examined for their properties in drug-release systems using two model Substances of different molecular weight, size, and polarity (caffeine and vitasyn blue). Neutral hydrogels were produced from functionalized AcGGM using hydroxyethyl methacrylate (HEMA) coupled via carbonyldiimidazole (CDI) and a co-monomer in a radical-initiated polymerization. Through a second modification reaction between the HEMA-modified AcGGM (M-AcGGM-methacrylated AcGGM) and maleic anhydride, a "double-modified" AcGGM (CM-AcGGM-carboxylated M-AcGGM) was successfuly, formed that could be cross-linked to form ionic hydrogels by the very same polymerization method. The neutral hydrogels showed drug release kinetics that could be easily regulated by changing the relative amount of the methacrylated AcGGM and its corresponding degree of methacrylation. The drug release rate and the Fickian swelling cl creased with an increase in these two aforementioned parameters. The ionic hydrogels showed quicker release kinetics and higher swelling capabilities than the corresponding nonionic gels did, especially at neutral conditions. Under acidic conditions, the release speed was lowered as expected because of protonation of carboxylic functionalities. Based on the findings we conclude that these novel hemicellulose-containing hydrogels have future prospects in drug release formulations, e.g., in a later stage of development for application in oral drug administration technology.

Place, publisher, year, edition, pages
2009. Vol. 112, no 4, 2401-2412 p.
Keyword [en]
hemicellulose, hydrogels, renewable resources, release, cross-linking, hemicellulose-based hydrogels, spruce picea-abies, renewable sources, biodegradable polymers, l. karst, wood, films, water
National Category
Other Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-18275DOI: 10.1002/app.29878ISI: 000264449500065Scopus ID: 2-s2.0-64249084593OAI: oai:DiVA.org:kth-18275DiVA: diva2:336321
Note
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Functional and Renewable Galactoglucomannan-based Hydrogels
Open this publication in new window or tab >>Functional and Renewable Galactoglucomannan-based Hydrogels
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Polysaccharides represent an important resource for a variety of products, from food via fuel supply to functional materials of every kind. Here they are, due to their natural diversity found in many special applications, e.g. in the biomedical sector.

Lately, a fairly unused group of polysaccharides, so called hemicelluloses, attracts more and more attention due to its high availability and promising properties.

This thesis presents the utilization of the water-soluble species O-acetyl-galactoglucomannan (AcGGM),   derived from softwood, as raw material for the synthetic design of functional hydrogels. AcGGM was used thanks to its great availability and high hydrophilicity rendering it an excellent material for hydrogels design.

For this purpose, a three-step-method was devised consisting of (1) the carbonyldiimidazole activation of primary hydroxylated vinylic compounds, (2) the substitution of hydroxyl groups of the AcGGM backbone with vinylic functions, and (3) radical crosslinking yielding in a hydrophilic three-dimensional network – a hydrogel.

Crosslinking strategies were varied from photo-crosslinking in DMSO to redox-initiated crosslinking in H2O with the objective of adapting the synthesis to benign conditions. Varying the crosslinking-species as well as the media was found to have a significant influence on the resulting gels’ properties, such as swelling capacity and G-modulus.  Here, swelling capacity could be affected to vary between ~0.6 to ~23 times of the gels self-weight and the G-modulus ranged from 0.4 to 145 kPa.

AcGGM and 2-hydroxy ethyl methacrylate (HEMA) gels were studied further and evaluated for their suitability as drug delivery systems for two model drugs (caffeine and Vitasyn Blue) varying in size, polarity and hydrophilicity. Here, the gels’ composition as well as a second modification with maleic acid anhydride was proved to affect the release properties significantly.

Based on our findings we conclude that the presented library is an important step to the promising future of these hydrogels based on the renewable resource AcGGM.

Place, publisher, year, edition, pages
Stockholm: Fiber- och polymerteknologi, 2009. iii, 48 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2009:22
Keyword
Polysaccharides, hydrogels, swelling, crosslinking, hemicellulose, release, polysackarider, hemicellulosa, hydrogel, läkemedelsfrisättning, förnyelsebar, tvärbindning.
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-10474 (URN)978-91-7415-350-7 (ISBN)
Presentation
2009-05-10, K1, KTH, Teknikringen 56, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
Gröna MaterialPulp Mill Biorefinery
Available from: 2009-05-26 Created: 2009-05-18 Last updated: 2010-11-03Bibliographically approved
2. Chemical Pathways for Galactoglucomannan-based Materials
Open this publication in new window or tab >>Chemical Pathways for Galactoglucomannan-based Materials
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Polysaccharides are an important resource for a variety of products, from food via fuel supply to functional materials of every kind. Due to their natural diversity they can be found in many special applications, e.g. in the biomedical sector and are the major renewable resource for materials of many kinds.

Recently, a fairly unused group of polysaccharides, so called

hemicelluloses, have attracted increasing attention due to their high availability and promising properties in combination with renewability and a potentially low price.

This thesis presents pathways for the chemical modification of the water-soluble hemicellulose

acetylated galactoglucomannan (AcGGM), enabling this raw material to be utilized in the synthetic design of new classes of materials.

Based on the chemical modification of the hydroxyl groups with crosslinkable groups in combination with the naturally high hydrophilicity, synthetic pathways for the production of functional hydrogels are presented. Thanks to the great availability and the native properties of AcGGM, this material was found to be an outstanding candidate in this respect and was adjudged to be a cheap and green resource for hydrogel design.

For this purpose, a three-step method was devised consisting of (1) the carbonyldiimidazole activation of primary hydroxylated vinylic compounds, (2) the substitution of hydroxyl groups of the AcGGM backbone with vinylic functions, and (3) radical crosslinking yielding a hydrophilic three-dimensional network – a hydrogel.

Crosslinking strategies were varied from photo-crosslinking in dimethyl sulfoxide (DMSO) to redox-initiated crosslinking in H

2O, with the objective of adapting the synthesis to benign conditions. Varying the crosslinking species as well as the medium was found to have a significant influence on the resulting gels’ properties, such as swelling capacity and G-modulus. Swelling capacity could be varied between ~0.6 and ~23 times the gel’s own weight and the G-modulus ranged from 0.4 to 145 kPa.

AcGGM and 2-hydroxy ethyl methacrylate (HEMA) gels were studied further and evaluated for their suitability as drug delivery systems for two model drugs (caffeine and Vitasyn Blue) varying size, polarity, and hydrophilicity of the drug to be II

released. It was found that the gels composition as well as a second modification with maleic acid anhydride affects the release properties.

Taking well-studied polysaccharide modification chemistry one step further and combining it with state of the art polymer synthesis, graft-copolymers of AcGGM were successfully synthesized via single-electron-transfer living-radical polymerization (SET-LRP). For this purpose, a macroinitiator was derived from AcGGM to enable a grafting of diverse hydrophilic and hydrophobic monomers from the AcGGM under benign conditions. Hybrid materials of the natural polymer AcGGM as a backbone with synthetic poly(methyl acrylate), poly(methyl methacrylate), poly(acrylamide), and poly(N-isopropyl acrylamide) graft-copolymers with a brush-like architecture were successfully synthesized, yielding molecular weights of up to 240∙10³ g ∙ mol

-1. As expected, the solubility and thermal properties were significantly altered, opening a wider range of potential applications.

We conclude that the presented chemical pathways are important steps towards a promising future for hemicelluloses as raw materials and their derivatives as shown for the resource AcGGM.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. viii, 76 p.
Series
Trita-CHE-Report, ISSN 1654-1081
Keyword
Polysaccharides, hemicelluloses, galactoglucomannan, renewable, chemical modification, hydrogels, swelling, crosslinking, release, SET-LRP, living polymerization, grafting, hybrid materials
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-34007 (URN)978-91-7415-989-9 (ISBN)
Public defence
2011-06-14, F3, Lindstedtsvägen 26, KTH, Stockholm, 09:00 (English)
Opponent
Supervisors
Note
QC 20110530Available from: 2011-05-30 Created: 2011-05-23 Last updated: 2011-05-30Bibliographically approved

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