<i>In vitro</i> degradation of a poly(ether urethane) by trypsin

Bouvier, M.; Chawla, A. S.; Hinberg, Irwin

doi:10.1002/jbm.820250607

Cited by 48 publications

(19 citation statements)

References 26 publications

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“…Only one of the treated elastomer specimens did not have its N/C ratio increased (Tables IV-VI). These results imply that the treated modules had an increased proportion of hard segments on the surface when compared to the untreated specimens [7], with the largest increase generally attributable to conditioning treatment 5 after both 10 and 100 days. Rearrangement of the hard segments to the polyurethane surface is facilitated by hydration fostered by the conditioning treatments [171.…”

Section: Correlation Of Elemental Property Changes With Structural Dementioning

confidence: 59%

“…Rearrangement of the hard segments to the polyurethane surface is facilitated by hydration fostered by the conditioning treatments [171. With the amount of degradation during treatment indicated by the change in N/C ratio [7], the "combined effects" treatment caused the greatest degradation among the polyurethane modules.…”

Section: Correlation Of Elemental Property Changes With Structural Dementioning

confidence: 99%

“…Modes of structural degradation of these materials may include chain scission, which can occur through mechanical, thermal, or chemical means, and/or crosslinking [3]. Previous investigators have focused on the biostability of implanted polyurethanes and their biodegradation in the body [4,5] and have found that thermal degradation, enzymatic hydrolysis, and oxidation play a major role in polyurethane implant rejection [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Structural degradation of polyurethane-based elastomeric modules

Stevenson

Kusy

1995

J Mater Sci: Mater Med

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Degradative characteristics were studied using specimens of three polyurethane-based elastomeric modules that were treated in solutions of varying acidity, oxygen content and temperature. After periods of 10 and 100 days, molecular weight distribution changes, mechanical property changes and elemental chemistry changes were studied using gel permeation chromatography (GPC), stress-relaxation testing and X-ray photoelectron spectroscopy (XPS), respectively. As determined through analyses of the molecular, mechanical, and elemental changes after treatment, the degradative mechanism was influenced by whether the polyurethane was polyester-based or polyether-based, and the degree of structural degradation was influenced by the type and duration of conditioning treatment. Degradation of the polyester-based materials after treatment was dominated by a chain scission mechanism; conversely, the degradation of the polyether-based material was dominated by a crosslinking mechanism. Among the conditioning treatments, the combined effects of an increase in acidity, oxygen content and temperature most influenced the degree of degradation with time, with the increase in temperature having the greatest effect of any of the single variables investigated.

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Section: Correlation Of Elemental Property Changes With Structural Dementioning

confidence: 59%

Section: Correlation Of Elemental Property Changes With Structural Dementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structural degradation of polyurethane-based elastomeric modules

Stevenson

Kusy

1995

J Mater Sci: Mater Med

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“…in the case of polyurethanes and polyethylenes. These include the interaction with lipids [3], enzymatic attack [4][5], microbiological breakdown [6], and degradation by reactive oxygen species [7] as well as mechanical wear [$-10].…”

Section: Introductionmentioning

confidence: 99%

Copolymers of 1,5-dioxepan-2-one and L- or D,L-dilactide: In vivo degradation behaviour

Löfgren

Albertsson

Zhang

et al. 1995

Journal of Biomaterials Science, Polymer Edition

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Copolymers of 1,5-dioxepan-2-one (DXO) and L-or D,L-dilactide have been synthesized and characterized. The molar ratio of the two monomers was around 20/80 of DXO and Lor D,L-lactide respectively. In vivo studies on rats revealed significant differences in tissue response between the semicrystalline DXO/L-LA copolymer and the amorphous DXO/D,L-LA copolymer. The materials were characterized pre-and post-implantation by size-exclusion chromatography (SEC), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and light-microscopy. Degradation seems to follow an autocatalytic hydrolysis mechanism. The amorphous copolymer was degraded at a faster rate and gave a less pronounced foreign body reaction as compared to the semicrystalline one.

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“…he enzymatic degradation of polymer systems has received considTerable attention in recent years [1][2][3][4][5][6][7][8][9]. The use of hydrogels as drug delivery systems has been investigated for both the parenteral and oral routes of administration [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

A Mechanistic Assessment of Enzyme-Induced Degradation of Albumin-Crosslinked Hydrogels

Shalaby

Chen

Park

1992

Journal of Bioactive and Compatible Polymers

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Pepsin-induced degradation of albumin-crosslinked hydrogels was studied as a function of the degree of albumin incorporation in the network and the concentration of pepsin. The degree of albumin incorporation, which represents the sum of chemical crosslinks and physical entanglements in the network, was controlled by changing the concentration of initiator in the monomer solution and the degree of vinylic functionality on albumin. Swelling characterization studies showed that the degree of hydrogel swelling decreased as the concentration of chemical initiator for the polymerization increased or as the degree of vinylic functionality on albumin increased. This indicated that the degree of albumin incorporation in the network increased by raising either the concentration of chemical initiator or the degree of albumin functionality. The rate and mechanism of gel degradation was also dependent on the degree of albumin incorporation in the network. A low degree of albumin incorporation resulted in a predominance of surface degradation while a high degree of albumin incorporation resulted in a predominance of bulk degradation. The transition from surface degradation to bulk degradation occurred at lower concentrations of chemical initiator when the degree of vinylic functionality on albumin was high. However, when the degree of vinylic functionality on albumin was low, the transition from surface degradation to bulk degradation was observed at higher concentrations of chemical initiator. The rate of gel degradation became slower as the concentration of pepsin was reduced. The results suggest that the rate and mechanism of hydrogel degradation was dependent on the steric constraints imposed by polymer chains of the network and on the conformational constraints of the albumin crosslinker.

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In vitro degradation of a poly(ether urethane) by trypsin

Cited by 48 publications

References 26 publications

Structural degradation of polyurethane-based elastomeric modules

Structural degradation of polyurethane-based elastomeric modules

Copolymers of 1,5-dioxepan-2-one and L- or D,L-dilactide: In vivo degradation behaviour

A Mechanistic Assessment of Enzyme-Induced Degradation of Albumin-Crosslinked Hydrogels

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