title: Self-complex formation of nicotinamide-modified dextran with carboxymethyl dextran using their degradation products.
abstract: A pseudo-metabolic cycle as a self-degradation system was designed: enzymatic degradation products from a polysaccharide generate oxidants which introduce a cationic charge into the polysaccharide chains, and can form a polyion complex with an anionic polysaccharide. As a component of such a system, dextran, with various degrees of nicotinamide substitution, was prepared. Its degradation by dextranase, redox reaction via glucose oxidase-catalysis, and polyion complex formation with carboxymetyl dextran (CMD) were examined. Nicotinamide-modified dextran (NA-Dex) with nine nicotinamide moieties per 100 glucose units was soluble in PBS and completely oxidized by > 100 mM H2O2. The oxidized type of NA-Dex was found to form a 1:1 complex with CMD. By the addition of dextranase, isomaltase, and glucose oxidase (GOD) to phosphate buffer solution of the reduced type of NA-Dex and CMD, the transmittance of the solution dropped, suggesting polyion complex formation via the oxidation of 1,4-dihydronicotinamide in NA-Dex by H2O2 generated from GOD-catalytic reaction. These findings are of great importance for designing a self-complex formation system aimed at biodegradable and osillative drug release.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa.
authors.forename: W
authors.initials: W
authors.lastname: Kamimura
authors.forename: T
authors.initials: T
authors.lastname: Ooya
authors.forename: N
authors.initials: N
authors.lastname: Yui
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D001673:Biodegradation, Environmental; D003911:Dextrans / Q000737:chemistry* / Q000493:pharmacokinetics; D007202:Indicators and Reagents; D007700:Kinetics; D008956:Models, Chemical; D009536:Niacinamide / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D001672:Biocompatible Materials; D003911:Dextrans; D007202:Indicators and Reagents; D009536:Niacinamide; C014392:carboxymethyl dextran