Nanocarrier drug delivery systems can greatly improve bioavailability, circulation times and delivery of drugs. Cellular uptake mechanisms of nanocarriers are greatly influenced by their physicochemical properties. In this master thesis, the characteristics of the 12 kDa amphiphilic block copolymer PVP-OD is investigated and the influence of nanocarrier size on the uptake in fibroblasts (CRL 2429) examined. Therefore, nanocarriers with a size of 220 nm (0.2 PDI) and 21 nm (0.244 PDI) were created by sonification or cosolvent evaporation, respectively. Both nanocarriers were taken up by a energy-dependent process, since inhibition led to a decrease of median fluorescent intensity (MFI) of 90 or 97 percent for sonificated and cosolvent evaporated nanocarriers, respectively. Colocalization of the cosolvent evaporated nanocarriers drug with LysoTracker indicated a possible macropinocytosis or clathrin-mediated endocytic uptake. However, further study with different endocytic inhibitors is necessary.