Chitin and chitosan, polysaccharides

This chapter will give you an overview of recent approaches for drug development, focusing on the function and roles of carbohydrates. O Section 2 will outline the biochemical functions of polysaccharide (neutral polysaccharide, chitin and chitosan, glycosaminoglycan, and synthetic polysaccharides) and glycopolymers and the perspectives of their medicinal/medical use. O Section 3 will outline recent biopharmaceutical research and development, utilizing... 

Hudson, S.M. and Smith, C. 1998. Polysaccharide Chitin and chitosan Chemistry and technology of then-use as structural materials. In Kaplan, D.L. (ed.). Biopolymers from Renewable Resources. Springer -Verlag, New York, pp. 96-118. 

Hudson SM, Smith C (1998) Polysaccharide chitin and chitosan chemistry and technology of their use as structural materials. In Kaplan DL (ed) Biopol)oners from renewable resources. Springer, New York, pp 96-118... 

Suginta W, Khunkaewla P, Schulte A. Electrochemical biosensor applications of polysaccharides chitin and chitosan. Chem Rev 2013 113 5458-5479. 

Among the natural polysaccharides, chitin and chitosan are very widely used in biomedical fields. Chitin is a biodegradable polymer of high molecular weight, and is one of the most common polysaccharides found in nature. It originates from the abundant exoskeletons of crustaceans. Like cellulose, chitin is a fiber, and it presents unique chemical and biological qualities that can be used in various medical applications. 

Many years ago chitin was seen as a scarcely appeahng natural polymer due to the variety of origins, isolation treatments and impurities, but the works of several analytical chemists and the endeavor of an increasing number of companies have qualified chitins and chitosans for sophisticated applications in the biosciences. Chemistry today offers a range of finely characterized modified chitosans for use in the biomedical sciences. Moreover, surprising roles of these polysaccharides and related enzymes are being unexpectedly discovered [351]. 

Another way to achieve desirable polymer properties is the modification of preformed polymers. This modification may take place on the reactive sites of the polymer chain through alkylation, hydrolysis, sulfonation, esterification, and other various reactions of polymers. Examples of natural polymers and their modifications are cellulose and its derivatives, chitin and chitosan, and polysaccharides. These are still to this day very important polymers for pharmaceutical applications. 

Polysaccharides including cellulose and its derivatives, agarose, dextran, starch, chitin, and chitosan (Figure 3.3) have been widely used as a support material in affinity chromatographic separations. 

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... 

Kurita, K., Kojima, T., Nishiyama, Y., and Shimojoh, M. 2000. Synthesis and some properties of nonnatural amino polysaccharides Branched chitin and chitosan. Macromolecules 33,4711—4716. 

Winterowd, J.G. and Sandford, P.A. 1995. Chitin and chitosan. In Food Polysaccharides and Their Applications (M.S. Alistair, ed.), pp. 441-462. Marcel Dekker, New York. 

A complete list of semi-synthetic heparinoids is outside the scope of this article. Products of sulfation of neutral polysaccharides include sulfates of starch, cellulose, - - xylan, dextran, " guaran, and synthetic polymers of o-glucose. A somewhat closer simulation of the structure of heparin was attempted by sulfating polysaccharides containing amino sugars or uronic acids or both, such as chitin and chitosan, " and the corresponding N-formyl, N-(car-boxymethyl), O-(carboxymethyl), and 5-carboxylated - deriva-... 

The book distills recent research conducted by the scientific community. It is arranged in four parts. Part I, Polysaccharides, covers hyaluronic acid, chitin and chitosan, starch and other natural polysaccharides. Polysaccharides have received more attention due to their numerous advantages such as their renew-ability, non-toxicity, biodegradability and ready availability. This interest has resulted in a great revolution leading to polysaccharides becoming on par with, and even superior to, synthetic materials. That is why a plethora of research studies have been undertaken to understand the potential of these natural polymers. 

Hyaluronic acid is a linear polysaccharide formed from disaccharide units containing N-acetyl-D-glucosamine and glucuronic acid. Since it is present in almost all biological fluids and tissues, hyaluronic acid-based materials are very useful in biomedical applications. After cellulose, chitin is the second most abundant natural polysaccharide resource on earth. Chitin and its de-acetylated derivative chitosan are natural polymers composed of N-acetylglucosamine and glucosamine. Both chitin and chitosan have excellent properties such as biodegradability, biocompatibility, non-toxicity, hemostatic activity and antimicrobial activity. Chitin and its derivatives are widely used in various fields of medicine. 

Ikeda N, Uno M, Flarata M, Nishiyama Y, Kurita K (2001) Synthesis of branched polysaccharides from linear giucans. In Uragami T, Kurita K, Fukamizo T (eds) Proceedings of the 8th international chitin and chitosan conference and 4th Asia pacific chitin and chitosan symposium, Yamaguchi, Japan, Kodansha Scientific Ltd, Tokyo, pp 368-369... 

Chitin, the precursor of chitosan, is a nitrogen containing polysaccharide and is second most abundant biopolymer after cellulose. It is widely distributed in the shells of crustaceans such as crabs, shrimps, lobsters, prawns, squilla, etc., as well as in the exoskeleton of marine zoo-plankton, including coral, jellyfish, and squid pens. About 20-40% chitin is present the exoskeleton of these animals. It is also present in smaller quantities in insects such as butter flies ladybugs, and the cell walls of yeast, mushrooms, and other fungi [Fig. 19.4]. However, since the crustacean shells [crabs, shrimps, lobsters, etc.] are waste products of food industry, these are commercially employed for the production of chitin and chitosan [1, 4, 18], It is believed that at least 10 gigaton of chitin is synthesized and degraded and it is also estimated that over 150,000 tons of chitin is available for commercial use annually. 

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