Hydrophobically Associating Alginate Derivatives: Surface Tension Properties of Their Mixed Aqueous Solutions with Oppositely Charged Surfactants

Babak, Valéry G.; Skotnikova, E.A.; Lukina, Irina G.; Pelletier, Sophie; Hubert, P.; Dellacherie, Édith

doi:10.1006/jcis.2000.6788

Cited by 89 publications

(70 citation statements)

References 22 publications

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“…Complex stacking configurations are regularly reported in experimental studies (e.g. Graham and Phillips 1979;Shogren and Biresaw 2007;Damodaran and Razumovsky 2003;Babak et al 2000). Therefore we adopt the round figure spread 1-100 9 10 -4 mol/m 2 as a reference range.…”

Section: Results: Surface Activitymentioning

confidence: 99%

“…Polysaccharides may be very insoluble when hydrophobic substituents are attached. We adopt the synthetic analog alginate as an initial proxy for the class of pure polysaccharides (Babak et al 2000). Lipids may be well represented either by long chain fatty acids or sterols (Kattner et al 1983;Loh et al 2008).…”

Section: Adsorption In the Modelmentioning

confidence: 99%

“…In controlled experiments, model heterogeneous polymers tend to form irregular and extremely complex structures spanning the water interface. Chains or filaments of hydrophiles may be suspended below a few hydrophobic constituents lining the surface (Babak et al 2000;Damodaran and Razumovsky 2003;Moore et al 2008). Stacked configurations could also be present in the marine environment, and so they are included here for potential sensitivity testing.…”

Section: Adsorption In the Modelmentioning

confidence: 99%

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Global distribution and surface activity of macromolecules in offline simulations of marine organic chemistry

et al. 2015

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Organic macromolecules constitute a high percentage of remote sea spray. They enter the atmosphere through adsorption onto bubbles followed by bursting at the ocean surface, and go on to influence the chemistry of the fine mode aerosol. We present a global estimate of mixed-layer macromolecular distributions, driven by offline marine systems model output. The approach permits estimation of oceanic concentrations and bubble film surface coverages for several classes of organic compound. Mixed layer levels are computed from the output of a global ocean ecodynamics model by relating the macromolecules to standard biogeochemical tracers. Steady state is assumed for labile forms, and for longer-lived components we rely on ratios to existing transported variables. Adsorption is then represented through conventional Langmuir isotherms, with equilibria deduced from laboratory analogs. Open water concentrations locally exceed one micromolar carbon for the total of proteins, polysaccharides and refractory heteropolycondensates. The shorter-lived lipids remain confined to regions of strong biological activity. Results are evaluated against available measurements for all compound types, and agreement is generally well within an order of magnitude. Global distributions are further estimated for both fractional coverage of bubble films at the air-water interface and the two-dimensional concentration excess. Overall, we show that macromolecular mapping provides a novel tool for the comprehension of oceanic surfactant patterns. These results may prove useful in planning

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Section: Results: Surface Activitymentioning

confidence: 99%

Section: Adsorption In the Modelmentioning

confidence: 99%

Section: Adsorption In the Modelmentioning

confidence: 99%

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Global distribution and surface activity of macromolecules in offline simulations of marine organic chemistry

et al. 2015

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“…It indicates that our systems do not adsorb at the air/water interface. Such results have been obtained for amphiphilic polysaccharides, in particular hydrophobically modified alginate 29 or pectin 30 with dodecyl groups and cholesteryl bearing pullulan. 8 These systems form aggregates in solution with the hydrophobic parts inside and the hydrophilic areas exposed to water.…”

Section: Surface Tension Measurementsmentioning

confidence: 68%

Self-organization of Water Soluble and Amphiphile Crosslinked Carboxymethylpullulan

Legros

Dulong

Picton

et al. 2008

Polym J

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The soluble state of amphiphile and crosslinked derivatives of carboxymethylpullulan was investigated by physicochemical analyses. This soluble state also called infinite sol was obtained from hydrogels after a short-time temperature treatment. The analyses show a large distribution in size for the species in solution (from some nanometers to some micrometers). Furthermore, they also reveal the presence of hydrophobic associations (intra and/or intermolecular) in addition to the chemical links. The nature of these hydrophobic interactions will depend on the polymer concentration and on the solvent used.KEY WORDS: Polysaccharide / Crosslinking / Hydrogels / Amphiphile / Self-organization / Hydrogels are suitable materials for drug delivery applications in biomedical and pharmaceutical fields. Indeed, active compounds can be easily entrapped and released, specially by responsive-stimuli devices which undergo phase transition or swelling-deswelling behaviour in response to environmental changes (temperature, pH, ionic strength, . . .). 1-3 Furthermore, they resemble natural living tissues by their ability to absorb and retain huge quantity of fluids and by their consistency, giving them a good biocompatibility. 4 Since several years, numerous studies have been interested in hydrogels based on polysaccharides and their derivatives because of their advantages over synthetic polymers. In fact, they are abundant, largely water soluble, biocompatible and descendent from renewable sources. 5 More recently, attention is focused on the development of amphiphilic networks able to transport amphiphilic and hydrophobic drugs. 6,7 Two majority ways are used to elaborate amphiphilic hydrogels based on polysaccharides. The most widespread way consists in grafting on the polymer backbone hydrophobic chains which self-aggregate in solution so creating cross-linking points but also hydrophobic domains. The most famous examples of this kind of systems are derivatives of pullulan bearing cholesteryl groups (CHP) which provide by self-aggregation particles able to complex hydrophobic molecules and proteins. [8][9][10][11][12][13] An other example consists of carboxymethylpullulan grafting by alkyl pendant groups. 14 The second technique consists in a chemical cross-linking with a hydrophobic agent. Few studies have been interested in this way although it gives in one step cross-links and amphiphilic character. So, Dulong et al. have elaborated amphiphilic carboxymethylpullulan networks using adipic dihydrazide 15 and N-hydroxysuccinimide, 16 whereas Coviello and Matricardi have choosen dibromohexan as cross-linking agent to obtain hydrogels from scleroglucan 17 and polygalacturonic acid. 18 We use the second method and dibromohexan to elaborate amphiphilic systems based on carboxymethylpullulan, an anionic derivative of pullulan (Figure 1). In a recent paper, 19 we showed that the cross-linking reaction was very fast, leading to creation of high crosslink density clusters as described by Hoffman. 20 On the other hand, we demonstrated ...

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“…The use of modified alginate in sustained-release drug delivery system design requires additional formulation or processing efforts to circumvent fast drug release in gastric region. Hydrophobically modified alginate-C12, alginate-C18 [10,[122][123][124] The alginate-Cn conjugate is amphiphilic in nature. The alkyl chains are preferentially bound to mannuronate residues than polyguluronate sequences.…”

Section: Graft Copolymer Physicochemical and Drug Release Propertiesmentioning

confidence: 99%

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

Wong

2011

Journal of Pharmacy and Pharmacology

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Objectives Use of alginate graft copolymers in oral drug delivery reduces dosage form manufacture complexity with reference to mixing or coating processes. It is deemed to give constant or approximately steady weight ratio of alginate to covalently attached co-excipient in copolymers, thereby leading to controllable matrix processing and drug release. This review describes various grafting approaches and their outcome on oral drug release behaviour of alginate graft copolymeric matrices. It examines drug release modulation mechanism of alginate graft copolymers against that of co-excipients in non-grafted formulations. Key findings Drug release from alginate matrices can be modulated through using either co-excipients or graft copolymers via changing their swelling, erosion, hydrophobicity/ hydrophilicity, porosity and/or drug adsorption capacity. However, it is not known if the drug delivery performance of formulations prepared using alginate graft copolymers is superior to those incorporating graft-equivalent co-excipient physically in a dosage form without grafting but at the corresponding graft weight, owing to limited studies being available. Conclusions The value of alginate graft copolymers as the potential alternative to alginate-co-excipient physical mixture in oral drug delivery cannot be entirely defined by past and present research. Such an issue is complicated by the lack of green chemistry graft copolymer synthesis approach, high grafting process cost, complications and hazards, and the formed graft copolymers having unknown toxicity. Future research will need to address these matters to achieve a widespread commercialization and industrial application of alginate graft copolymers in oral drug delivery

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Hydrophobically Associating Alginate Derivatives: Surface Tension Properties of Their Mixed Aqueous Solutions with Oppositely Charged Surfactants

Cited by 89 publications

References 22 publications

Global distribution and surface activity of macromolecules in offline simulations of marine organic chemistry

Global distribution and surface activity of macromolecules in offline simulations of marine organic chemistry

Self-organization of Water Soluble and Amphiphile Crosslinked Carboxymethylpullulan

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

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