Abstract: The present invention concerns a composition comprising complexes of cationic chitosan oligomers derived from the cationic polysaccharide chitosan, wherein said cationic oligomers contain a weight fraction of less than 20% of oligomers with a Degree of Polymerization (DP)<10 in addition to a weight fraction of less than 20% with DP>50, and a nucleic acid. These compositions comprising well-defined cationic chitosan oligomers having a certain distribution of chain lengths, and nucleic acid are advantageous to achieve delivery of the nucleic acid into cells of a selected tissue, and to obtain in vivo expression of the desired molecules encoded for by the nucleic acid.

Abstract: The present invention concerns a novel composition comprising a nucleic acid; and a chitosan containing branching groups covalently linked to the amino groups wherein said branches are selected from the following groups; alkyl with 2 or more carbon atoms, monosaccharides, oligosaccharides or polysaccharides. The composition is particularly useful as a non-viral gene delivery system. The composition facilitates the introduction of the nucleic acid into the cells to which it is administrated, as well as the expression of the function of the nucleic acid.

Abstract: The present invention concerns a composition comprising complexes of cationic chitosan oligomers derived from the cationic polysaccharide chitosan, wherein said cationic oligomers contain a weight fraction of less than 20% of oligomers with a Degree of Polymerization (DP)<10 in addition to a weight fraction of less than 20% with DP>50, and a nucleic acid. These compositions comprising well-defined cationic chitosan oligomers having a certain distribution of chain lengths, and nucleic acid are advantageous to achieve delivery of the nucleic acid into cells of a selected tissue, and to obtain in vivo expression of the desired molecules encoded for by the nucleic acid.

Abstract: The present invention concerns a composition comprising complexes of cationic chitosan oligomers derived from the cationic polysaccharide chitosan, wherein said cationic oligomers contain a weight fraction of less than 20% of oligomers with a Degree of Polymerization (DP)<10 in addition to a weight fraction of less than 20% with DP>50, and a nucleic acid. These compositions comprising well-defined cationic chitosan oligomers having a certain distribution of chain lengths, and nucleic acid are advantageous to achieve delivery of the nucleic acid into cells of a selected tissue, and to obtain in vivo expression of the desired molecules encoded for by the nucleic acid.

Abstract: The present invention concerns a novel composition comprising a nucleic acid; and a chitosan containing branching groups covalently linked to the amino groups wherein said branches are selected from the following groups; alkyl with 2 or more carbon atoms, monosaccharides, oligosaccharides or polysaccharides. The composition is particularly useful as a non-viral gene delivery system. The composition facilitates the introduction of the nucleic acid into the cells to which it is administrated, as well as the expression of the function of the nucleic acid.

Abstract: The present invention is directed to a composition and pharmaceutical preparations for introducing nucleic acids including oligo- or poly-nucleotide into cells in a host tissue by a delivery system and a method of preparing such a composition. The composition for delivery of nucleic acids comprises polymeric carrier particles that are essentially free of groups having a positive electric charge and the nucleic acids are provided essentially on the surface of the particles. The carrier particle is insoluble in water but suitably it is able to absorb water quickly.