Abstract: The invention relates to a new method of preparation of a hyaluronan derivative with an aldehydic group in the position (6) of the polysaccharide glucosamine part. The hyaluronic acid oxidation can be performed by means of TEMPO/NaCIO or TEMPO/TCC systems in a protic environment with or without the presence of anorganic salts. Thus prepared aldehyde can be used for binding amines, diamines, amino acids, peptides and other compounds containing an amino group, e.g. by means of the reductive amination with NaBH3CN in water or in a water-organic solvent system. When a diamine or compounds containing three or more amino groups are used, cross-linked hyaluronan derivatives can be prepared. Cross-linked derivatives can be also prepared by a reaction of the aldehyde with a hyaluronan substituted by an amino-alkyl group HA-alkyl-NH2.

Abstract: The invention relates to the preparation and use of ?,?-unsaturated aldehyde of hyaluronan having a double bond in the positions 4 and 5 and an aldehydic group in the position 6 of the glucosamine part of the polysaccharide. The method of preparation is based on dehydration of hyaluronan having an aldehydic group in the position 6 of the glucosamine part of the polysaccharide. Two methods have been described, which are dehydration in a solution or heating in solid state in absence of solvents, bases or other additives. This derivative allows stabilization of conjugates of hyaluronan with amino compounds by means of a multiple bond from the aldehyde side, and therefore, it is possible to effectively immobilize practically any compound containing an amino group to such modified hyaluronan in physiological conditions. In case of using a diamine or compounds or polymers containing three or more amino groups, it is possible to prepare crosslinked hyaluronan derivatives.

Abstract: The present invention describes novel amphoteric materials based on crosslinked hyaluronic acid, according to the general formula (I), and a method of preparation of said materials. Further, the invention relates to the material containing entrapped active agents (e.g. drugs, growth factors etc.) and a method of preparation thereof. Moreover, the present invention relates to the use of said materials for controlled release systems, in tissue engineering, wound dressing or tissue regeneration.

Abstract: The invention relates to a new method of preparation of a hyaluronan derivative with an aldehydic group in the position (6) of the polysaccharide glucosamine part. The hyaluronic acid oxidation can be performed by means of TEMPO/NaCIO or TEMPO/TCC systems in a protic environment with or without the presence of anorganic salts. Thus prepared aldehyde can be used for binding amines, diamines, amino acids, peptides and other compounds containing an amino group, e.g. by means of the reductive amination with NaBH3CN in water or in a water-organic solvent system. When a diamine or compounds containing three or more amino groups are used, cross-linked hyaluronan derivatives can be prepared. Cross-linked derivatives can be also prepared by a reaction of the aldehyde with a hyaluronan substituted by an amino-alkyl group HA-alkyl-NH2.

Abstract: The invention relates to a hyaluronic acid derivative and methods of preparation and modification of a hyaluronan derivative with an aldehydic group in the position (6) of the polysaccharide glucosamine part. The oxidation of the hyaluronic acid can be performed by means of Dess-Martin periodinane (DMP) agent. The prepared aldehyde can be used for binding amine, diamine, amino acid, peptide and other compounds containing an amino group, e.g. by means of the reductive amination with NaBH3CN in water or in a water-organic solvent system. When a diamine or compounds containing three or more amino groups are used, cross-linked hyaluronan derivatives can be prepared. Cross-linked derivatives can also be prepared by the reaction of the aldehyde with a hyaluronan substituted by an amino-alkyl group HA-alkyl-NH2.

Abstract: This invention relates to a novel method of preparation of hyaluronic acid derivatives by means of a reaction of the hyaluronic acid with the complex (O-acyl-O?-alkyl carbonate-substituted pyridine) of the general formula R—CO—O—CO—O—R1 and R25C5N. The reaction takes place in DMSO in the presence of an external base, forming O-acylated products. The method leads to higher substitution degrees and shorter reaction times compared to the known analogues, hi case the agent comprises two or more functional groups R(CO—O—CO—O—R1)n, crosslinked hyaluronic acid derivatives are formed.

Abstract: The invention relates to the modification of hyaluronic acid by means of a protonized DTPA bis anhydride in a non-basic polar aprotic solvent in absence of any external base to form crosslinked products. The reaction runs via the formation of a complex and the acylating agent is the hyaluronan co-cation itself, i.e. protonized DTPA bis anhydride. The final crosslinked derivative (linker) comprises three carboxylic groups and three tertiary amines which are capable of complexing various metals effectively. The final DTPA crosslinked hyaluronic acid may also be hydrophobized by means of mono, bis or tris functional alkylating agents.