Polyelectrolyte complexes chitosan

Keywords Chitosan Nanoparticles Microspheres Chemically modified chitosans Polyelectrolyte complexes Oral and nasal administration Nerve, cartilage and bone regeneration Wound dressing... 

Polyelectrolyte complexes composed of various weight ratios of chitosan and hyaluronic acid were found to swell rapidly, reaching equilibrium within 30 min, and exhibited relatively high swelling ratios of 250-325% at room temperature. The swelling ratio increased when the pH of the buffer was below pH 6, as a result of the dissociation of the ionic bonds, and with increments of temperature. Therefore, the swelling ratios of the films were pH-and temperature-dependent. The amount of free water in the complex films increased with increasing chitosan content up to 64% free water, with an additional bound-water content of over 12% [29]. 

A simple example of gel formation is provided by chitosan tripolyphosphate and chitosan polyphosphate gel beads the pH-responsive swelling abihty, drug-release characteristics, and morphology of the gel bead depend on polyelectrolyte complexation mechanism and the molecular weight. The chitosan beads gelled in pentasodium tripolyphosphate or polyphosphoric acid solution by ionotropic cross-hnking or interpolymer complexation, respectively. 

The chitosan-heparin polyelectrolyte complex was covalently immobilized onto the surface of polyacrylonitrile membrane. The immobilization caused the water contact angle to decrease, thereby indicating an increase in hy-... 

For the preparation of spray-dried polyelectrolyte complexes, the polyanion was dissolved in dilute NH4HCO3 solution and mixed with the chitosan carbamate solution just before spray-drying. The excess NH4HCO3 decomposed thermally between 60 and 107 °C on the other hand, the carbamate function released carbon dioxide under the effect of the temperature at which the spray-drier was operated, thus regenerating chitosan at the moment of the polyelectrolyte microsphere formation (Fig. 5). 

Fig. 5 Microspheres manufactured from the polyelectrolyte complex of chitosan carbamate and ammonium alginate in ammonium bicarbonate solution. Muzzarelli, original data, 2004...

Kang HS, Park SH, Lee YG et al (2007) Polyelectrolyte complex hydrogel composed of chitosan and poly(y-glutamic acid) for biological application Preparation, physical properties, and cytocompatibility. J Appl Polym Sci 103 386-394... 

Polyelectrolyte complexes have also been studied as tablet matrices for controlled release applications. For example, the interpolymer complexes of chitosan with pectin and acacia were investigated as tablet matrices for release of chlorpromazine HCL [353]. The complex formed in situ by mixing chitosan with either pectin or acacia displayed the most efficient sustained release (compared to either pectin, acacia or a preformed complex). The results were attributed to the swelling and gel-forming capacity of the freshly formed complex in contrast to the preformed version. 

Chitin and chitosan derivatives have also been studied as blood compatible materials both in vivo and in vitro [520], Anticoagulant activity was greatest with O sulfated N acetyl chitosan, followed by N,0 sulfated chitosan, heparin, and finally sulfated N acetyl chitosan. The lipolytic activity was greatest for N,0 sulfated chitosan followed by heparin. The generally poor performance of chitosan was attributed to polyelectrolyte complexes with free amino groups present on the membrane surface. The O sulfate or acidic group at the 6 position in the hexosamine moiety was identified as the main active site for anticoagulant activity. 

Kawashima, Y., et al. 1985. Novel method for the preparation of controlled-release theophylline granules coated with a polyelectrolyte complex of sodium polyphosphate-chitosan. J Pharm Sci 74 264. 

Fig. 13 Polyelectrolyte complex formed by layer-by-layer assembly of dextran sulfate and chitosan...

Another approach to reach delayed release from chitosan matrices are ionic interactions with polyanions. The formation of a polyelectrolyte complex membrane prevents early drug release. Via this method microcapsules can be formed between chitosan and alignate or even nanoparticles can be derived upon the complexation of chitosan with the polyanion tripolyphosphate. 

Incorporated HRP into polyelectrolyte complexes with chitosan of different molecular weights (MW 5-150 kDa) The complex formed by 0.001% chitosan with a molecular weight of 150 kDa was most stable when immobilized on foamed polyurethane, it retained at least 50% of the initial activity for 550 days [43]... 

Veselova IA, Kireiko AV, Shekhovtsova TN (2009) Catalytic activity and the stability of horseradish peroxidase increase as a result of its incorporation into a polyelectrolyte complex with chitosan. Appl Biochem Microbiol 45 125-129... 

It has been attempted to perform template polymer syntheses without using biological sources. Concepts focus on the formation of a complex between monomer molecules and a present macromolecule [4,480], This way the monomer will get preorganized and the polymerization is supposed to follow a zip mechanism controlled by the length and the configuration of the template polymer, offering replication of the molecular weight and control of the stereo structure. Polymerization of acrylic acid in the presence of poly(ethyleneimine), N-vinylimidazole/ poly(methacrylic acid) or acrylonitrile with poly(vinylacetate) have been described [469,470,471,472,473]. Recently the preparation of solid polyelectrolyte complexes from chitosan and sodium-styrenesulfonate has been reported [481]. 

Denunziere A, Ferrier D, Domard A. Chitosan-chondritoin sulfate and chi-tosan-hyaluronate polyelectrolyte complexes. Physico-chemical aspects. Car-bohydr Polym 1996 29 317-323. 

Hugerth A, Lelham NC, Sundelof LO. The effect of charge density and conformation on the polyelectrolyte complex formation between carrageenan and chitosan. Carbohydr Polym 1997 34 149-156. 

Muzzarelli et al. (2000) described a method for coating prosthetic articles with chitosan-oxychitin. Plates of titanium (Ti) and its alloys were plasma sprayed with hydroxyapatite and glass layers, and subsequently a chitosan coat was deposited on the plasma-sprayed layers using chitosan acetate. These layers were treated with 6-oxychitin to form a polyelectrolytic complex. This complex was optionally contacted with l-ethyl-3-(3-dimethylami-nopropyl) carbodiimide at 4°C for 2 hours to form amide links between the two polysaccharides, or acetylation with acetic anhydride in methanol to obtain a chitin film. In all cases, the modified coats were insoluble, uniformly flat, and smooth. Prosthetic materials coated with chitosan-oxychitin were capable of provoking colonization by cells, osteogenesis, and osteointegration. 

Composite scaffolds by incorporating 80 wt% HA in the polyelectrolyte complex matrix of chitosan and poly(acrylic acid) (PAA) in the ratio... 

Sailaja GS, Ramesh P, Kumary TV et al (2006) Human osteosarcoma cell adhesion behaviour on hydroxyapatite integrated chitosan-poly(acrylic acid) polyelectrolyte complex. Acta Biomater 2 651-657... 

Mao JS et al (2004) A preliminary study on chitosan and gelatin polyelectrolyte complex cytocompatibility by cell cycle and apoptosis analysis. Biomaterials 25(18) 3973-3981... 

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