This disertation thesis is focused on the study of physico-chemical interactions of hyaluronan (with molecular weights from 10 to 1750 kDa) with cationic surfactants measured using uncommon technique named high resolution ultrasonic spectroscopy. Densitometer was also used for the study of these interactions, in measuring of density and ultrasonic velocity of hyaluronan with different molecular weight in dependence on elevated temperature (25 50 °C). The aim is the determination of critical micelle concentration (CMC) and critical aggregation concentration (CAC) of the suractants in the absence and in the presence of hyaluronan with various molecular weights. Interactions in this system are important for the design of the systems for the targeted delivery, especially for the drugs. The experiments were made in water and sodium chloride solution. The significant breakpoint in the ultrasonic velocity showed changes in the system hyaluronan-surfactant.