Due to the advances of molecular biotechnology and bioinformatics, there is a strong increase of new candidate drug molecules. However, their transport to the actual site of action and bioavailability are decisive issue. In order to enable adequate delivery of small or larg drug molecules some special formulation will be required. Current advances in material science and nanotechnology promise the development of new generations of drug carriers for these active substances for diagnostic and therapeutic purposes. Today are mostly investigated liposomes, nanoparticles, dendrimers, nanotubes etc. where size, geometry, porosity, dispersity, surface chemistry are highly defined. Carrier composition and structure promises control over biological fate. In the talk three examples studied in our lab will be used to illustrate these points: preparation of drug loaded solid lipid nanoparticles, interactions of nanoparticles with the cells and surfactant selection for adequate nanoparticles production that causes minimal toxicity to HEK 293 cells, while preventing nanoparticles aggregation. These observations indicate that in the design and development of novel nanoparticles for drug delivery a combination of factors such as composition, size and surface properties influence bioavailability, uptake into the cells and toxicity. Current work focuses on systematic variation of these parameters to develop carrier system with designed function.