One of the most important mechanisms for multidrug resistance (MDR) phenotype is believed be the P-gp-mediated drug efflux. The consequent lowering of the intracellular concentrations of many commonly-used chemotherapeutic drugs, such as doxorubicin (Dox), has been addressed by P-gp inhibition via covalent attachment of MDR drugs to carriers.This project aimed to develop new drug binding peptide structures able to traverse cell membranes and to investigate their potential in the 'non'-covalent' deiivery of Dox in drug-resistant (KD30) cells.