Carboxymethyl-chitin

In concentrated NaOH, chitin becomes alkali chitin which reacts with 2-chloroethanol to yield 0-(2-hydroxyethyl) chitin, known as glycol chitin this compoimd was probably the first derivative to find practical use (as the recommended substrate for lysozyme). Alkali chitin with sodium monochloroacetate yields the widely used water-soluble 0-carboxymethyl chitin sodium salt [118]. The latter is also particularly susceptible to lysozyme, and its oUgomers are degraded by N-acetylglucosaminidase, thus it is convenient for medical appHcations, including bone regeneration. 

Sodium carboxymethyl chitin and phosphoryl chitin had most evident influences on the crystallization of calcium phosphate from supersaturated solutions. They potently inhibited the growth of hydroxyapatite and retarded the rate of spontaneous calcium phosphate precipitation. These chitin derivatives were incorporated into the precipitate and influenced both the phase and morphology of the calcium phosphate formed (flaky precipitate resembling octacalcium phosphate instead of spherical clusters in the absence of polysaccharide) [175]. 

FU(1), chitosan-5FU(2), a-l,4-polygalactosamine-5FU(3), partially N-acetylated a-l,4-polygalactosamine-5FU(4), hyaluronic acid-5FU(5), dextran-5FU(6), and 6-0-carboxymethyl chitin(CM-chitin)-5FU(7). 

There are several reports on the coating of bone-like hydroxyapatite onto natural polymer substrates. Kawashita et at. [57] reported that carboxymethylated chitin and gellan gum gels, which have carboxyl groups, can form hydroxyapatite on their surfaces in SBF if they are treated with a saturated Ca(OH)2 solution in advance, while curdlan gel, which has no carboxyl group, does not form hydroxyapatite in SBF, even if it is treated with Ca(OH)2 solution. These results support the hypothesis that carboxyl groups induce hydroxyapatite nucleation. Kokubo et at. [58,59] reported that non-woven fabrics of carboxymethylated chitin and alginate fibers also form hydroxyapatite on their surfaces in SBF if they are treated with Ca(OH)2 solution. 

Affinity chromatography was carried out on columns prepared with lightly carboxymethylated chitin, which is known to be a poor substrate for lysozyme. Both native lysozyme and regenerated 13-105 were bound to the column at pH 7 and eluted at pH 3. As controls, the basic proteins cytochrome c and pancreatic RNase A, as well as concanavalin A and a-amylase, were not bound from the same solvent at pH 7. These findings constitute a third line of evidence for formation of native-like structure in regenerated 13-105. 

Characterization of Enzyme-Substrate Complex by use of CM-Chitin (Carboxymethyl Chitin). CM-chitinwas prepared by carboxymethylation of chitin according to the method of Imoto, Hayashi and Funatsu (13). The ozonized lysozyme (1.3 mg) solutions at different pHs were neutralized with NaOH or HCl to pH 8.0 and the poured into the column (1.5 X 4 cm.) containing white cotton-like Cm-chitin ( 65 mg.), which was equilibrated with 0.1 M Tris-Cl buffer pH 8.0. Aliquots were eluted first with 0.1 M Tris-Cl pH 8.0 and then with 0.2 M HAc. The absorbance of the fractions was measured spectrophotometrically at 280 nm. 

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]. 

Chitins Carboxymethyl chitin Mitomycin C Amide bond between drug amine and carrier carboxyl None N/A N/T Conjugate showed less anticancer activity than free drug against L1210 leukemia, but greater activity against B16 melanoma 52... 

SCM-Chitin (sulfated and carboxymethylated chitin) (Mw = 10000 to 60000) Inhibits cell attachment and migration of BI6-BL6 melanoma cells through extracellular matrix 64... 

Carboxymethyl-chitin (CM-chitin), as a water-soluble anionic polymer, is the second most studied derivative of chitin after chitosan. The carbox-ymethylation of chitin is imdertaken in a similar manner to that of... 

In this report, focusing to carboxymethyl chitin/chitosan and carboxymethyl cellulose, we studied the reactivity of water radiolysis products with polymer chains using the pulse radiolysis method as the first step to clarify early gelation process of polymer radicals related to crosslinking. 

Figure 1. Structure of carboxymethyl chitin/chitosan (left)and carboxymethyl...

Chemical modifications of chitin are generally difficult owing to the lack of solubility because reactions under heterogeneous conditions are accompanied by various problems such as the poor extent of reaction, difficulty in region-selective substitution, structural ambiguity of products and partial degradation due to the severe reaction conditions. Carboxymethyl chitin is one of the most studied chitin derivatives, obtained by adding monochloro-acetic acid to chitin previously treated with sodium hydroxide at different... 

Shalumon, K. T., Binulal, N. S., Selvamurugan, N., Nair, S. V., Deepthy, M., Furuike, T. (2009]. Electrospinning of carboxymethyl chitin/poly (vinyl alcohol] nanofibrous scaffolds for tissue engineering applications, Carboh rdn ol m., 77, 863-869. 

There are several synthetic composite materials and their applications in tissue engineering are versatile. For instance, in one study a composite of carboxymethyl-chitin (CM-chitin) with hydroxyapatite (HAp) was examined for its ability to repair bone in animals. New bone formation of CM-chitin-HAp composite was superior to that of CM-chitin, HAp, and control (Tokura and Tamura, 2001). The porous CM-chitin-HAp composite was also a functional... 

Tokura, S. Tamura, H. (2001) O-carboxymethyl-chitin concentration in granulocytes during bone repair. Biomacromolecules, 2, 417-21. 

Chitin, a waste material from crab and shrimp processing, is poly(N-acetyl-D-glucosamine). The de-acetylated form, chitosan, is primarily used in water purification but is also used as a chemical feedstock. For example, chitosan can be depolymerized to the monomer, which is used as a hair-setting agent in shampoo and hair conditioner. In the future, graft polymers of chitosan may form biodegradable films. Already, carboxymethylated chitin is approved as a food wrap. 

Atomergic Allantoln. See Allantoin Atomergic Carboxymethyl Chitin. See Sodium carboxymethyl chitin... 

P-Chitin. See Chitin Chitinase. See Glucanase Chitin, 6-(carboxymethyl) ether. See Carboxymethyl chitin Chitin, carboxymethyl, sodium salt. See... 

Sodium carboxymethyl chitin Chitin, deacylated. See Chitosan Chitin Liq. Chitisoi. See Carboxymethyl chitin Chitobiase Chitodextrinase. See Glucanase Chitogiycan . See Carboxymethyl chitosan Chitosamine. See Glucosamine Chitosan... 

Chitosolbe. See Carboxymethyl chitin Chives. See Chives (Allium schoenoprasum) Chives (Allium schoenoprasum)... 

C12-15 alkyl salicylate Canolamidopropyl betaine Canolamidopropyl ethyidimonium ethosulfate Capramide DEA Capryl hydroxyethyl imidazoline Capryloyl collagen amino acids Capryloyl hydrolyzed collagen Capryloyl hydrolyzed keratin Capryloyl keratin amino acids Caprylyl hydroxyethyl imidazoline Carboxymethyl chitin Carpronium chloride Casein Ceresin Ceteth-20 Cetethyidimonium bromide Cetethyl morpholinium ethosulfate Cetrimonium methosulfate Cetrimonium saccharinate Cetrimonium tosylate... 

PPG-5-ceteth-20 PPG-20 methyl glucose ether PPG-20 methyl glucose ether distearate Propylene glycol Propyltrimonium hydrolyzed wheat protein Pyridoxine dilaurate Quaternium-22 Serum albumin Serum protein Silk Silk (Serica) extract Sodium carboxymethyl chitin Sodium hyaluronate Sodium hyaluronate dimethylsilanol Sodium lactate Sodium mannuronate methylsilanol Sodium PCA methylsilanol Sodium PG-propyl thiosulfate dimethicone Sodium polyglutamate Soluble collagen Sorbeth-20 Sorbitol Sphingolipids Sucrose Sulfated castor oil... 

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