Chitosan, biodegradable polymers

Biodegradable polymers, both synthetic and natural, have gained more attention as carriers because of their biocompatibility and biodegradability and therewith the low impact on the environment. Examples of biodegradable polymers are synthetic polymers, such as polyesters, poly(orfho-esters), polyanhydrides and polyphosphazenes, and natural polymers, like polysaccharides such as chitosan, hyaluronic acid and alginates. 

Chitosan Chitosan is a nontoxic, biodegradable polymer obtained by hydrolysis of chitin, a natural polysaccharide that is a chief component of the crustacean exoskeleton. Unmodified chitosan is soluble in acidic media and has significant muco-adhesive properties. 

Several of the most effective polymeric delivery systems were polyamidoamine den-drimers (220) and polyethyleneimines (PEI) (221). Being non-biodegradable, these synthetic polymers posed a potential toxicity to cell therefore, biodegradable polypeptides like PLL and protamine were used for condensation and delivery of gene, but they had limited efficacy in transfection (222, 223). They were usually used with cationic lipids to obtain enhanced transfection activity (178,201). Among the biodegradable polymers, chitosan... 

Biodegradable polymer nanoparticles are PEG-coated poly(lactic acid) (PLA) nanoparticles, chitosan (CS)-coated poly(lactic acid-glycolic acid) (PLGA) nanoparticles, and chitosan (CS) nanoparticles. These nanoparticles can carry and... 

There are many kinds of natural biodegradable polymers. They are classified into three types according to their chemical structures, i.e., polysaccharides, polypeptides/proteins and polynucleotides/nucleic acids. Among them, polysaccharides, such as cellulose, chitin/chitosan, hyaluronic acid and starch, and proteins, such as silk, wool, poly( y-glutamic acid), and poly(e-lysin), are well known and particularly important industrial polymeric materials. 

There are several kinds of natural biodegradable polymers in addition to bacterial PHAs, such as proteins, nucleic acids and polysaccharides. Among them, particulary important polymers such as industrial materials are polysaccharides, such as starch, cellulose, chitin and chitosan. The solid-state structure and properties of starch and amylose [127], cellulose [128] and chitin... 

The use of chitosan as a means of controlling the release of amino-acids has been also investigated by Rhone-Poulenc (ref. 5). Chitosan (deacetylated chitin) is extracted from shrimp and crab shells. It is known as a non-toxic, biodegradable polymer (Fig. 5). It is insoluble in water at neutral pH and has the capacity to dissolve at low pH values. Chitosan solutions are prepared by dissolving the polymer in dilute acetic acid. Stearic acid and oleic acid are the hydrophobic constituents in the chitosan-based coatings. 

Chitosan has received considerable attention as a functional biopolymer for diverse pharmaceutical and biomedical applications. It is a nontoxic, biocompatible, and biodegradable polymer. Chitosans can be formulated as nanocarriers mainly by... 

Hyaluronic acid is a naturally occurring polysaccharide comprising monosaccharide sequences with carboxylic or acetamido side groups. Early production of hyaluronic acid, a biodegradable polymer similar to chitosan, was achieved through extraction of natural tissues, and the evolution of hyaluronic acid technology was made possible after its successful production in sufficient quantities as a fermentation product. The key evolution of... 

Chitosan is obtained from the deacetylation of chitin, which is found in marine environments. Because it is insoluble in water, chitosan is dissolved in acidic solutions before being incorporated into biodegradable polymer films. It can also be plasticized with glycerol to obtain a kind of thermoplastic material like, for instance, plasticized starch (Epure, 2011]. 

S.W. Shalaby, J.A. DuBose, M. Shalaby, Chitosan Based Systems, Absorbable and Biodegradable Polymers, vol. 6, CRC Press, Boca Raton, 2004, pp. 77-89. 

Mucha, M., Piekielna, J. and Wieczorek, A. (1999) Characterization and morphology of biodegradable chitosan/synthetic polymer blends. Macromolecular Symposia, 144, 391-412. 

Sudhakar, Y. N., M. Selvakumar, and D. K. Bhat. 2013. LiC104-doped plasticized chitosan and poly(ethylene glycol) blend as biodegradable polymer electrolyte for supercapacitors. Ionics 19 277-285. 

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