The invention relates to a method for coupling low-molecular weight substances to a starch-derived modified polysaccharide. The binding interaction between the modified polysaccharide and the low-molecular weight substance is based on a covalent bond which is the result of a coupling reaction between the terminal aldehyde group or a functional group of the modified polysaccharide molecule resulting from the chemical reaction of this aldehyde group and a functional group of the low-molecular weight substance which reacts with this aldehyde group or with the resulting functional group of the polysaccharide molecule. The bond directly resulting from the coupling reaction can be optionally modified by a further reaction to the aforementioned covalent bond. The invention further relates to pharmaceutical compositions that comprise conjugates formed in this coupling process and to the use of said conjugates and compositions for the prophylaxis or therapy of the human or animal body.
