The present invention relates to compositions containing nanoparticles and uses of said composition for transferring therapeutically active substances into cells by means of specifically coated nanoparticles. The chemical design of the particles is such that a large amount thereof is absorbed into the cells. No direct bond between nanoparticle and the therapeutically active substance is required for the transfer into the cells. Thanks to said transfer, an increased efficacy of the substance and simultaneously reduced systemic toxicity is achieved, i.e. an increase in the efficacy while the side effects are reduced.