The invention relates to a dextran functionalized with at least one hydrophobic alpha-amino acid residue, wherein said alpha-amino acid is grafted or linked to the dextran by a linker arm and a function. The term “hydrophobic amino acid residue” is intended to mean the product of coupling between the amine of the amino acid and an acid carried by the linker arm, wherein said dextran is amphiphilic at neutral pH. In one embodiment, the hydrophobic amino acid is selected from tryptophan derivatives such as tryptophan, tryptophanol, tryptophanamide and 2-indoleethylamine, and alkali cation salts thereof. The present invention also relates to a pharmaceutical composition containing one of the dextrans according to the invention.
