Associative behaviour of hydrophobically modified carboxymethylpullulan derivatives

Bataille, Isabelle; Huguet, J.; Müller, G.; Mocanu, Georgeta; Carpov, A.

doi:10.1016/s0141-8130(97)01158-6

Cited by 82 publications

(62 citation statements)

References 12 publications

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“…19,22 The degree of substitution (number of carboxylic groups per anhydroglucose unit) was determined by conductimetric titration according to the method of Eyler 23 and found about 0.96. The average molar masses were determined by F4/MALLS measurements (Table III).…”

Section: Methodsmentioning

confidence: 99%

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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Section: Methodsmentioning

confidence: 99%

Self-organization of Water Soluble and Amphiphile Crosslinked Carboxymethylpullulan

Legros

Dulong

Picton

et al. 2008

Polym J

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“…Three glucose units in maltotriose are connected through an -1,4-glycosidic bond, whereas consecutive maltotriose units are connected to each other by an -1,6 glycosidic bond. Pullulan is produced from starch by the fungus Aureobasidium pullulans (Bataille et al, 1997;Glinel et al, 1999). …”

Section: Pullulanmentioning

confidence: 99%

“…The nanogels formed complexes with various drugs and proteins by hydrophobic interaction and released them upon exposure to specific proteins (Akiyoshi et al, 1997;Akiyoshi et al, 1993;Cheng et al, 2008). Hydrophobically-modified pullulans of moderate molar mass and differing in hydrophobic modification ratio, charge ratio and the nature of the hydrophobic chains were prepared (Bataille et al, 1997;Glinel et al, 1999;Fischer et al, 1998). Poly ( DL -lactide-coglycolide)-grafted pullulan can form self-assembling nanospheres and controll adriamycin release.…”

Section: Modified Pullulanmentioning

confidence: 99%

“…This nanoparticlehas several hydrophobic domains of four to five associated cholesteryl moieties. carboxymethylpullulan Alkyl bromide (octyl, decyl or dodecyl) (Bataille et al, 1997;Glinel et al, 1999) Modification: Hydrophobically-modified carboxymethylpullulans (HMCMPs) were obtained by a synthetic pathway adapted from that used by Della Valle for gellan and Fischer et al for pectin. Pullulan with molecular weight of 50,000-100,000 (g/mol)…”

Section: Pullulanmentioning

confidence: 99%

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Nanoparticles Based on Modified Polysaccharides

Namazi¹,

Fathi²,

Heydari³

2012

The Delivery of Nanoparticles

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“…For many applications and mainly for improving the rheology of dispersions a compromise between optimal hydrophobic characteristics and water solubility must be found. Some studies have reported the metastable character of amphiphilic polymers derived from hydroxyethylcellulose [12], carboxymethylpullulan [13] and maleic anhydride/ethyl vinyl ether copolymers [14]. However only Esquenet and Buhler [15] have studied in more detail the ageing of solutions of chitosan modified with 2% of C 6 -C 14 alkyl groups.…”

Section: Introductionmentioning

confidence: 99%

Metastable state of amphiphilic polysaccharide solutions

Simon¹,

Mocanu²,

Picton³

et al. 2004

E-Polymers

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This communication reports the time-dependent viscometric behaviour of amphiphilic pullulan (with varied amount of grafted octyl groups, C 8 ) solutions as a function of age and temperature. For lower C 8 amount, no ageing effects were observed. With high amount of octyl-bearing groups, the solution exhibits a strong increase of viscosity caused by an increase of intermolecular associations and the simultaneous decrease of intramolecular associations. After longer time, a collapse of chains has been observed. This behaviour is favoured with concentration and temperature. These results evidence the metastable character of amphiphilic polymers in aqueous solution.

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Associative behaviour of hydrophobically modified carboxymethylpullulan derivatives

Cited by 82 publications

References 12 publications

Self-organization of Water Soluble and Amphiphile Crosslinked Carboxymethylpullulan

Self-organization of Water Soluble and Amphiphile Crosslinked Carboxymethylpullulan

Nanoparticles Based on Modified Polysaccharides

Metastable state of amphiphilic polysaccharide solutions

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