A series of 1,4-substituted arylalkyl piperazinederivatives were synthesized and studied with the aim to obtain potent P-gp-dependent multidrug-resistant (MDR) reversers. The new compounds were designed on the basis of the structures of our previous arylamine ester derivatives endowed with high P-gp-dependent multidrug resistance reversing activity. All new compounds were active in the pirarubicin