Chitin applications

Montgomery, M.T., N.A. Welschmeyer, and D.L. Kirchman. 1990. A simple assay for chitin application to sediment trap samples from the subarctic Pacific. Mar. Ecol. Prog. Ser. 64 301-308. 

Lack of the amine group "NH2 makes chitin almost chemically inactive. In addition, the availability of chitin as the second most abundant material after cellulose allows its use as an excipient in processing solid drug dosage forms. This facilitates its use with other common excipients, namely microcrystalline cellulose (MCC), lactose, starch, and calcium hydrogen phosphate. Consequently, this monograph will focus on chitin applications as a solid dosage form excipient. 

Thus, based on material applications, the following polymers are important natural rubber, coal, asphaltenes (bitumens), cellulose, chitin, starch, lignin, humus, shellac, amber, and certain proteins. Figure 4 shows the primary structures of some of the above polymers. For detailed information on their occurrence, conventional utilization, etc., refer to the references cited previously. 

Five articles on polysaccharide helices solved prior to 1979 have appeared in the volumes published between 1967 and 1982.2-6 The first was a review on X-ray fiber diffraction and its application to cellulose, chitin, amylose, and related structures, and the rest were bibliographic accounts. Since then, X-ray structures of several new polysaccharides composed of simple to complex repeating units have been successfully determined, thanks to technological advances in fiber-diffraction techniques, the availability of fast and powerful computers, and the development of sophisticated software. Also, some old models have been either re-... 

Recent progress of basic and application studies in chitin chemistry was reviewed by Kurita (2001) with emphasis on the controlled modification reactions for the preparation of chitin derivatives. The reactions discussed include hydrolysis of main chain, deacetylation, acylation, M-phthaloylation, tosylation, alkylation, Schiff base formation, reductive alkylation, 0-carboxymethylation, N-carboxyalkylation, silylation, and graft copolymerization. For conducting modification reactions in a facile and controlled manner, some soluble chitin derivatives are convenient. Among soluble precursors, N-phthaloyl chitosan is particularly useful and made possible a series of regioselective and quantitative substitutions that was otherwise difficult. One of the important achievements based on this organosoluble precursor is the synthesis of nonnatural branched polysaccharides that have sugar branches at a specific site of the linear chitin or chitosan backbone [89]. 

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]. 

UrbanczykGW (1997) In Goosen MFA (ed) Applications of Chitin and Chitosan. Technomic, Basel, p. 281... 

Therefore, the ability of certain POs to bind with chitin is a widespread phenomenon and -possibly - connected with the defence reactions of the organisms to pathogen attacks. Since it was shown that some biogenic molecules - such as chitooligosaccharides or salicylic acid -can activate an anionic POs, we might suggest that an application of these compounds optimises the process of anionic PO isolation with a chitin. 

CHITIN. Chitin is the exoskeletal polymer used by most anthropods for structural and protective body parts. It is available in large quantities but is difficult to use. The limited solubility of chitin in all but a few very special solvents and the very limited chemistry and technology available to alter chitin into useful materials has hindered the application of this material to articles of commerce. 

Chitosan features far more than chitin in research into applications. This is largely due to their difference in solubility characteristics, chitosan being more amenable to practical manipulation. Chitin is in fact rather more intractable than cellulose, since it is insoluble in those solvents, such as cuprammonium hydroxide, that are commonly used to dissolve cellulose. Chitin is soluble in hot concentrated solutions of certain inorganic salts capable of... 

Natural and synthetic aminopolysaccharides have recently attracted much attention because of their unique stmctures and properties that are generally different from those of normal polysaccharides such as cellulose. For example, chitin is the most abundant aminopolysaccharide among the naturally occurring polysaccharides and has been of great interest in numerous scientific and application field (Scheme 1) [3]. 

Chitin and Chitosan Sources, Chemistry, Biochemistry, Biochemistry, Physical Properties and Applications Skjak-Braek, G. Anthousen, T. Sanford, P., Eds. Elsevier Applied Science New York, NY, 1989 835 pp. 

Chitin is a polysaccharide similar to cellulose except that the OH at C-2 is replaced by an acetamido group (CH3CONH). Chitin is the main component of the hard external covering (exoskeleton) of crustaceans such as lobsters, crabs, and shrimp. Like cellulose, the processing of chitin into polymeric products is limited by its insolubility and decomposition without melting. The availability in huge quantities has encouraged many attempts to find commercial applications of chitin, but very few have been found to be economically feasible. 

Polyelectrolytes have recently found application in the development of pH sensitive liposomal controlled release systems. This application arises from the fact that polyelectrolytes may be used both to stabilize liposomes, and to disrupt liposomes in a pH dependent manner. Although the use of liposomes in oral pharmaceutical compositions has been discussed [424], liposomes generally suffer from poor stability and are therefore prone to leakage of the entrapped active agents. To overcome this problem, several authors have stabilized the liposomes using polyelectrolytes. For example, Tirrell and coworkers have employed ionene [425], and polyethylene imine) [426] to stabilize liposomes. Similarly, Sato and coworkers have studied maleic acid copolymers [427], and Sumamoto and coworkers have studied liposomes [428] coated with polysaccharides. In related work, Kondo and coworkers have emphasized the use of carboxymethyl chitin to produce artificial red blood cells [429-435]. 

Kim, S. K. (2010). Chitin, Chitosan, Oligosaccharides and Their Derivatives Biological Activities and Applications. CRC Taylor Francis, USA (pp. 666). 

Chitosan, the most abundant marine mucopolysaccharide, is derived from chitin by alkaline deacetylation, and possesses versatile biological properties such as biocompatibility, biodegradability, and a non-toxic nature. Due to these characteristics, considerable attention has been given to its industrial applications in the food, pharmaceutical, agricultural, and environmental industries. Currently, chitosan can be considered as a potential marine nutraceutical because its remarkable biological activities have been investigated and reported, in order to exploit its nutraceutical... 

Uchida, Y., Izume, M., and Ohtakara, A. (1989). Preparation of chitosan oligomers with purified chitosanase and its application. In "Chitin and Chitosan", (G. Skjak-Braek,... 

Harish Prashanth, . V. and Tharanathan, R. N. (2007). Chitin/chitosan Modifications and their unlimited application potential. Trends Food Sci. Technol. 18,117-131. 

In other applications of the marine colloids use may be made of chitosan, a polyelectrolyte obtained from chitin by deacetylation to provide a positively charged polymer with a controllable charge density. 

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