[Mechanism of the reaction of glutaraldehyde with chitosan].

The regularities of the reaction of aminopolysaccharide chitosan with glutaraldehyde (GA) have been considered. The equilibrium forms of GA in water have been thoroughly studied by NMR spectroscopy. It has been established that at pH 5.6, the exchange of the protons of O=CHCH2 groups for deuterium occurs, indicating the presence of an anion, a product of the first stage of the aldol reaction; at pH > 7.2, the formation of the products of an aldol reaction and aldol condensation takes place. The kinetics of the reaction between the amino groups of chitosan and GA, the kinetics of gel formation in chitosan solutions in the presence of GA, and the kinetics of changes in the rigidity of gels formed have been studied by UV spectroscopy. IR spectra of cross-linked chitosan have been obtained. It has been shown that chitosan catalyzes the polymerization of GA to form inhomogeneous products; in this process, the length of oligomeric chains in modified or cross-linked chitosan and the concentration of coupled bonds increase with the GA concentration and pH of the reaction medium.

[Preparation of biodegradable porous films for use as wound coverings].

We studied the preparation of polymeric films formed from solutions of poly-3-hydroxybutyrate and poly-epsilon-caprolactone in chloroform and methylene chloride. A morphological study of film chips (electron microscopy) showed that solvent evaporation results in the formation of a heterogeneous structure with interpenetrating pores (1-20 microm). We proposed a new method for introducing the proteolytic enzyme and the aminopolysaccharide chitosan into the composition of polyester films. Composite films possessed necrolytic activity and were characterized by increased hydrophilicity. Properties of enzyme-containing films from a mixture of polymers (proteolytic activity, porous structure, and increased hydrophilicity) account for their use in the preparation of biodegradable wound coverings.