Characterization of crosslinked guar by thermal analysis

Gliko-Kabir, Irit; Penhasi, Adel; Rubinstein, Abraham

doi:10.1016/s0008-6215(99)00025-7

Cited by 45 publications

(23 citation statements)

References 23 publications

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“…[19,20] Indeed, we verified experimentally that mannose residues can effectively bind covalently the carrier (about 0.4 mmol per gram of support) by reacting the p-nitrophenyl b-d-mannoside with the pre-activated amino resin (Scheme 1). A further factor that is expected to drive the reaction toward the formation of the covalent bond is represented by the fact that the reaction takes place on a solid phase, so that the equilibrium between the synthetic and hydrolytic reactions is shifted toward the bond formation, as previously demonstrated.…”

Section: Resultsmentioning

confidence: 88%

In Silico Analysis of Enzyme Surface and Glycosylation Effect as a Tool for Efficient Covalent Immobilisation of CalB and PGA on Sepabeads®

et al. 2007

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This study presents a computational analysis of the structures of lipase B from Candida antarctica (CalB) and two penicillin G acylases (PGAs), from eukaryotic and prokaryotic sources, respectively. Molecular simulations were used to point out the regions of the enzymes that are prone to interact with immobilisation supports. In order to evaluate the accessibility of the active site, the location of the amino acid residues involved in the formation of covalent bonds with the polymers was visualised. The mapping of the distribution of hydrophobic and hydrophilic regions on the enzyme surface provided a view of the areas of the protein that can establish either hydrophobic or hydrophilic interactions with the carriers. Experimental data obtained from the immobilisation of the enzymes on supports bearing different chemical functionalities suggest the involvement of the glycan moiety in enzyme-polymer interactions. In the case of PGA the glycan moiety can constitute an extra site for the covalent linkage of the enzyme on the polymer.

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Section: Resultsmentioning

confidence: 88%

In Silico Analysis of Enzyme Surface and Glycosylation Effect as a Tool for Efficient Covalent Immobilisation of CalB and PGA on Sepabeads®

et al. 2007

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“…According to Soppirnath and Aminabhavi [42] the second stage corresponds to the loss of hydroxyl groups as water molecules and scission of the main chain of GG. Gliko-Kabir et al [15] reported that the thermal degradation of polysaccharides occurs through random scission of the glycosidic bonds, followed by a further decomposition, and the degradation of GG is caused by a sequence of cleavages of galactose and mannose from the GG backbone.…”

Section: Thermal Stabilitymentioning

confidence: 99%

“…This effect was observed to be stronger in the cross-linked natural polymers due to changes in the polymer structures. For example, the thermal stability of GG was improved by cross-linking with low amounts of glutaraldehyde, but decreased when high amounts of the same cross-linker were used [15] . In agreement with this scenario, in the GG films crosslinked with 10%, 20% and 30% of EDC, the temperature of the maximum degradation rate for stage 2 decreased to values lower than 300 °C, suggesting a loss of thermal stability.…”

Section: Thermal Stabilitymentioning

confidence: 99%

“…In agreement with this scenario, in the GG films crosslinked with 10%, 20% and 30% of EDC, the temperature of the maximum degradation rate for stage 2 decreased to values lower than 300 °C, suggesting a loss of thermal stability. One explanation for this behavior is that with the cross-linking process and, as a consequence, the formation of intra-cross-linking reactions within the GG chain, the hydrogen bonds, and in turn the polymer structure, was affected reducing the thermal stability [15] .…”

Section: Thermal Stabilitymentioning

confidence: 99%

“…According to the literature, only a few agents have been used to cross-link GG. For example, Gliko-Kabir et al [15][16][17] studied the cross-linking of GG using glutaraldehyde and trisodium trimetaphosphate. The systems were evaluated in terms of the thermal behavior and the viability of their use as delivery systems.…”

Section: Introductionmentioning

confidence: 99%

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Preparation, characterization and properties of films obtained from cross-linked guar gum

BANEGAS¹,

ZORNIO²,

BORGES³

et al. 2013

Polímeros

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Abstract:In this study the viability of using guar gum to form films was investigated along with the effectiveness of the cross-linking process employing 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) as the cross-linking agent. In addition, the cross-linked films were evaluated considering the water absorption, thermal stability and mechanical properties. The cross-linking process of guar gum films was confirmed by the low solubility in water and through infrared analysis. The results shown that the properties evaluated were affected by the cross-linking process due to changes in the polysaccharide structure. For example, the swelling behavior and water vapor absorption decreased with an increase in the amount of EDC. The EDC content (10-30%) also affected the polymer structure and hydrogen bond formation, reducing the thermal stability of the system.

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Natural polysaccharides as targeting tools of drugs to the human colon

Rubinstein¹

2000

Drug Dev. Res.

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Characterization of crosslinked guar by thermal analysis

Cited by 45 publications

References 23 publications

In Silico Analysis of Enzyme Surface and Glycosylation Effect as a Tool for Efficient Covalent Immobilisation of CalB and PGA on Sepabeads®

In Silico Analysis of Enzyme Surface and Glycosylation Effect as a Tool for Efficient Covalent Immobilisation of CalB and PGA on Sepabeads®

Preparation, characterization and properties of films obtained from cross-linked guar gum

Natural polysaccharides as targeting tools of drugs to the human colon

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