The modification reaction of amylose with nicotinoyl chloride using pyridine as catalyst was studied. The structure of the resulting polymers was determined by means of IR, I H and I' C NMR spectroscopy. A linear dependence of the reaction rate on polymer, nicotinoyl chlori ie and pyridine was found. The activation energy was found to be 32,2 kJ/mol. The hydrolysis in the heterogeneous phase showed that the release of the active compound is dependent upon t i e hydrophilic character of the modified amylose polymers, the temperature as well as the pH value of the medium.