The present invention provides a biodegradable polycation composition for delivery of an anionic macromolecule, comprising a polysaccharide chain having an amount of saccharide units ranging from 2 to 2000 and at least one grafted oligoamine per 5 saccharide units, wherein said oligoamine is selected from the group consisting of a linear, branched and cyclic alkyl amine having at least two amino groups.