Chitosan, derivatives

Changes in the backbone of the sulfonic acid azo dyes often produce drastic changes in properties of the materials. The disulfonic acid (5) is somewhat similar to (3), but is used to color leather red (77). More esoteric dyes have also been developed based on sulfonic acid metal complexes and chitosan-derived materials (78,79). 

In fact, one of the major applications of chitosan and some of its many derivatives is based on its ability to bind precious, heavy and toxic metal ions. Another article reviews the various classes of chitosan derivatives and compares their ion-binding abihties under varying conditions, as well as the analytical methods to analyze them, the sorption mechanism, and structural analysis of the metal complexes. Data are also presented exhaustively in tabular form with reference to each individual metal ion and the types of compounds that complex with it under various conditions, to help reach conclusions regarding the comparative efficacy of various classes of compounds [112]. 

A novel fiber-reactive chitosan derivative was synthesized in two steps from a chitosan of low molecular weight and low degree of acetylation. First, a water-soluble chitosan derivative, N-[(2-hydroxy-3-trimethylammonium)-... 

The complexing of chitosan and its basic derivatives with anionic substances is paralleled by compatibility with cationic and nonionic compounds. Similarly, the anionic derivatives of chitosan show complex formation with cationic agents and are compatible with anionic and nonionic compounds. The capability of these chitosan derivatives to complex with certain metal ions, notably those of the transition series, is also important, having possibilities for the removal of metal salts from effluent. The hierarchy in terms of binding capacity is Cr(III) < Cr(II) < Pb(II) < Mn(II) < Cd(II) < Ni(II) < Fe(II) < Co(II). 

T0382 Humboldt State University, Chitosan Derivative... 

T0382 Humboldt State University, Chitosan Derivative T0390 IBC Advanced Technologies, Inc., SuperLig Ion Exchange Resins T0394 Idaho National Engineering Laboratory/Brookhaven National Laboratory, Modified Sulfur Cement Encapsulation... 

Chitosan, a polymer derived from shellfish, has been chemically altered to enhance its metalbinding properties. Chitosan derivatives have potential for treating wastewater contaminated with... 

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. 

Aiba, S. (1989). Studies on chitosan 2. Solution stability and reactivity of partially N-acetylated chitosan derivatives in aqueous media. Int. ]. Biol. Macromol. 11, 249-252. 

Zhang, C., Ding, Y., Ping, Q.E., Yu, L.L. (2006). Novel chitosan-derived nanomaterials and their micelle-forming properties. Journal of Agricultural and Food Chemistry, 54, 8409-8416. 

Qaqish, R.B., Amiji, M.M. (1999). Synthesis of a fluorescent chitosan derivative and its application for the study of chitosan-mucin interactions. Carbohydrate Polymers, 38, 99-107. 

Yoshioka, H., Nonaka, K., Fukuda, K., Kazama, S. 1995. Chitosan-derived polymer-surfactants and their micellar propertiesBiosci. Biotechnol. Biochen59 1901-1904. 

Cationic chitosan derivatives, such as /Y-trimethyl chitosan chloride, increase the paracellular delivery of macromolecules due to the interaction between the positive charges of chitosan and anionic glycoproteins on the surface of the enterocytes. Other chitosans, e.g., chitosan hydrochloride, were reported to shift specific cations required for the efficient closing of tight junctions [21] or reorganize the protein structure of tight junctions [22]. This topic is reviewed in a separate chapter of this book (Chapter 3). 

Sandri, G., et al. 2004. Assessment of chitosan derivatives as buccal and vaginal penetration... 

Just recently a series of other quaternized chitosan derivatives have been synthesized and characterized, namely, A,A-dimethyl, A-ethyl chitosan (DMEC) (Bayat et al. 2006), A-methyl, A,A-diethyl chitosan (DEMC) (Avadi et al. 2004) and A,A,A-triethyl chitosan (TEC) (Avadi et al. 2003). In a comprehensive study (Sadeghi et al. 2008a, b) the four quaternized derivatives of chitosan, trimethyl chitosan (TMC), diethylmethyl chitosan (DEMC), triethyl chitosan (TEC) and dimethylethyl chitosan (DMEC) with degree of substitution of approximately 50% were synthesized and their effect on the permeability of insulin across intestinal Caco-2 monolayers was studied and compared with chitosan both in free-soluble form and in nanoparticulate systems. Trans-epithelial electrical resistance (TEER) studies revealed that all four chitosan derivatives in free-soluble forms were able to decrease the TEER value in the following order TMC>DEMC>TEC = DMEC>chitosan, indicating their... 

Sadeghi, A.M.M., Dorkoosh, F.A., Avadi, M.R., Bayat, A., Delie, F., Gurny, R., Rafieeh-Tehrani, M. and Junginger, H.E. (2008a) Permeation enhancer effect of chit-osan and chitosan derivatives comparison of formulations as soluble polymers and nanoparticulate systems on insulin absorption in Caco-2 cells. Eur. J. Pharm. Bio-pharm. 70 270-278. 

Thanou, M. (2000) Chitosan Derivatives in Drug Delivery. Trimethylated and Carboxy-methylated Chitosan as Safe Enhancers for the Intestinal Absorption of Hydrophilic Drugs, PhD Thesis, Leiden University, Leiden, pp. 91-108. 

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