Cation interactions in gellan: An x-ray study of the potassium salt

Chandrasekaran, R.; Puigjaner, Luís; Joyce, Karen L.; Arnott, Struther

doi:10.1016/0008-6215(88)84020-5

Cited by 202 publications

(74 citation statements)

References 16 publications

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“…The model compound structures used in the calculations on the gellan linkages are based on X-ray crystal data of the polysaccharide potassium salt obtained by Chandrasekaran et al [9]. The model α-(1 → 4) glucan was based on the crystal structure of β-maltose monohydrate [10] and was modified using a PC-based molecular modelling package.…”

Section: Computational Methodologymentioning

confidence: 99%

Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates

Wilson

Durran

Howlin

et al. 1996

Elect J Theoret Chem

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SUMMARYThe effect of basis set quality and glycosidic conformation on the calculated chemical shieldings of the C-1 and C-4 glycosidic carbon atoms of some naturally and commercially important model β-(1 → 4), α-(1 → 4) and α-(1 → 3) linkage systems have been investigated using ab initio molecular orbital coupled Hartree-Fock gauge included atomic orbital (CHF-GIAO) methods. The STO-3G, 3-21G, 4-31G and 6-31G * * basis sets have been tested in our calculations.

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Section: Computational Methodologymentioning

confidence: 99%

Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates

Wilson

Durran

Howlin

et al. 1996

Elect J Theoret Chem

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“…Under suitable condition, the native gellan gum forms weak gels [12], however, it forms stiff, brittle gels on deacylation [11] as in agarose. The physicochemical investigations for deacylated gellan gum were done by many workers [76]- [78]. A tertiary structure of the polymer was reported to consist of two identical left-handed, 3-fold double helices in the solid state [78] similar to that of agarose.…”

Section: Gelation Mechanism Of Gellan Gummentioning

confidence: 99%

The Principle of Polysaccharide Gels

Tako¹

2015

ABB

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For several decades attention has been directed to natural polysaccharide gels and synthesized polymer gels. The structure-function relationships at molecular level in water of polysaccharides, κ-carrageenan, ι-carrageenan, agarose (agar), and gellan family of polysaccharides (gellan, welan, rhamsan, S-657, deacetylated rhamsan and native gellan gum), which are industrially useful polysaccharides extracted from family of red seaweeds and bacteria, in principle are discussed on the view point of rheological aspects. The polysaccharide molecules (0.1% -1.0%) play a dominant role in the center of the tetrahedral cavities occupied by water molecules (99.0% -99.9%), and the arrangement is similar to a tetrahedral structure in a gelation process. The cage and hydrophobic effect play thermal dynamically dominant role in gelation process which gives lowest entropy to electrons of sugar residues. Though the chemical structure of these polysaccharides similar each other, their rheological (gelling) characteristics are quite different. Many investigations about the gelling properties of the polysaccharides have been undertaken to elucidate the structure-function relationship, but no other researchers have established mechanism at the molecular level. There is consistency in our investigations. Thus, the rheological analysis is one of significant methods for understanding the structure-function relationship of polysaccharides in aqueous media. The discussion provides many important information not only in academic field, but also in industrial one, such as food, cosmetic, pharmaceutical, drug delivery and tissue industries, and biotechnology.

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“…It is a 2008) and consists of repeating tetrasaccharide units of glucose, glucuronic acid, glucose and 36 rhamnose residues (Chandrasekaran et al, 1988). Gellan gum is an EU approved food additive 37 (E418) that has been investigated by several groups for applications in pharmaceuticals (Deasy and …”

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confidence: 99%

Evaluation of gellan gum fluid gels as modified release oral liquids

Mahdi

Conway

Smith

2014

International Journal of Pharmaceutics

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Oral liquids are often preferred for drug administration to patients for whom swallowing is difficult, however formulating modified release versions can be challenging. A potential route to achieve modified release in oral liquids is by using fluid (sheared) gels formed by introducing a shear field during gelation in gel-forming biopolymers. These fluid gels can act as pourable viscoelastic fluids but retain true gel micro/nano structure. Here, we have demonstrated that fluid gels have potential as paediatric oral liquids preventing release of ibuprofen in simulated gastric fluid. Subsequent release at pH 7.4 was affected by the duration of exposure and magnitude of acid pH with a linear relationship between onset of release and the preceding acidic exposure duration. Delayed release was a result of increasing gel stiffness, a consequence of the acidity of the initial release media and exposure time. A much faster release rate was measured when exposure time in acid was 10 min compared with 60 min. This study highlights the potential to design fluid gels that are tuned to have a specified stiffness at a particular pH and exposure time. This could enable the preparation oral liquids with modified release behaviour.

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Cation interactions in gellan: An x-ray study of the potassium salt

Cited by 202 publications

References 16 publications

Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates

Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates

The Principle of Polysaccharide Gels

Evaluation of gellan gum fluid gels as modified release oral liquids

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Cation interactions in gellan: An x-ray study of the potassium salt

Cited by 202 publications

References 16 publications

Ab initio CHF‐GIAO 13C nuclear shielding calculations on carbohydrates

Ab initio CHF‐GIAO 13C nuclear shielding calculations on carbohydrates

The Principle of Polysaccharide Gels

Evaluation of gellan gum fluid gels as modified release oral liquids

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Product

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Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates

Ab initio CHF‐GIAO ¹³C nuclear shielding calculations on carbohydrates