The idea behind this research was inspired by the development of new drug delivery systems. Most of the active substances are released from the drug immediately and their action is immediate, therefore, an effort is made to find a formulation that will release the active substance in a controlled way over a long period. After the preparation of the drug, it is important that the drug is stable and releases the active substance in a specific part of the gastrointestinal tract. In this paper, the research was carried out in several steps, which is the preparation of pellets using two different methods. The impregnated pellets were prepared by mixing microcrystalline cellulose and sodium chloride in a mass ratio of 70:30, extruding the mixture, spheronizing and then washing to remove NaCl to achieve a porous structure of pellets. Dronedarone hydrochloride (DNR), in form of nanosuspension, is vacuum-impregnated into the pellet pores. Pellets marked as 100 mg and 400 mg were prepared by direct incorporation of dronedarone hydrochloride into microcrystalline cellulose pellets during extrusion, and then spheronized. The specific surface area, pore size distribution, particle size distribution and morphology of pellets were examined and the content of active substance was determined. The release rate of dronedarone from the pellets was investigated by in vitro method. A first-order model describes the resulting release profiles. The results showed that the method of direct incorporation of DNR into pellets is a more effective method of application of the active substance over vacuum impregnation because it gives the possibility of obtaining higher doses of the drug. A first-order model described the kinetics of DNR release, and the release rate constant confirmed the slowest DNR release from 100 mg pellets. The coating of the pellets furthermore slows down the release of the active substance. The DNR release profiles of 400 mg 60c pellets are closest to the release profiles of the Multaq tablet, and additional modifications can be achieved by coating. This study showed that different pellet preparation and application of DNR and coating material could achieve better release control. Dosage forms of various active substance contents can be prepared and the multiple advantages of pellets over tablets as a dosage form can be utilized.