Mucoadhesive nanoparticles are the form of a new therapeutic system with great potential for local and systemic drug delivery. Compared to conventional therapy, they offer a number of advantages such as targeted drug delivery, prolonged action, drug degradation protection and side effect reduction. The aim of this study was to prepare muchoadhesive nanoparticles of the antibiotic cefixime and perform their physical characterization, optimize the conditions of preparation, to examine the physical properties of nanoparticles after the lyophilization process and to test the drug incorporation. For the experimental part of work, the development and validation of the HPLC method was carried out. The mucoadhesive nanoparticles of cefixime were prepared by a simple desolvation method and their size, index of polydispersity, zeta potencial and percentage of the incorporated drug were determined. The zeta potential of the particles ranged from -41,4 to -43,1 mV, which indicates the stability of nanoparticle dispersion. The results obtained showed that the volume of added water influences the size and index of polydispersity of nanoparticles. The content of the drug in nanoparticles was determined by high performance liquid chromatography (HPLC). From the results obtained 1:3 the ratio of organic and aqueous phases gave the highest percentage of drug incorporation into nanoparticles. After the lyophilization process of nanoparticles with two different cryoprotectans, the size, index of poydispersity and zeta potencial of nanoparticles were again determined. Although drug incorporation into nanoparticles is low, target drug delivery and better bioavilabitity allow better effect than conventional systems. According to the results of earlier studies and our own experimental data, mucoadhesive nanoparticles shows great potential in the development of new therapeutic systems.