A novel polycyanoacrylate-based bone-substituting foam material has been developed, which provides independent release of two polypeptide actives followed by biodegradation and bone substitution.
The kinetics of homogeneous hydrolysis of polyacrylonitrile in an aqueous solution of sodium car bonate and the chemical structure of the resulting copolymer are studied by FTIR spectroscopy, 13 C NMR analysis, and titration methods. It is found that hydrolysis in the presence of sodium carbonate does not include the stage of amidine formation and does not result in the complete exhaustion of nitrile groups in a polymer. The designed partial hydrolysis method permits the use of polyacrylonitrile for the synthesis of the copolymer with a predominant unit alternation; this copolymer is identical in terms of chemical structure to the Rohacell copolymer obtained through block copolymerization of acrylonitrile and methacrylic acid.
13 C nuclear magnetic resonance, paramagnetic resonance, and ultraviolet spectroscopy and highresolution gel permeation chromatography were used to investigate the process of periodate oxidation of carboxymethyl cellulose and the structure and molecular weight characteristics of its oxidised forms produced under different conditions. It was shown that, in solution and in the solid state, aldehyde groups in the oxidised units exist in the form of cyclic hemiacetals. An examination was made of the existence of all the main cyclic intramolecular hemiacetal structures, and the most probable were proposed. The influence of the degree of periodate oxidation on the molecular weight characteristics and hydrolytic stability of dialdehyde carboxymethyl cellulose was studied.
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