Multidrug resistance (MDR) mediated by overexpression of MDR1 P-glycoprotein (P-gp) is one of the best characterized transporter-mediated barriers to successful chemotherapy in cancer patients. Chemosensitizers are the agents that increase the sensitivity of multidrug- resistant cells to the toxic influence of previously less effective drugs. In an attempt to find such vital chemosensitizers, a series of N10-substituted-2-chloroacridone analogous (1– ...