New prodrugs consisting of a beta-D-glucuronic acid linked to a MDR reversa
l agent (verapamil, quinine or dipyridamole) through a self-immolative spac
er were synthesized. Four of them were selected for their reduced cytoxicit
y and beta-glucuronidase enzymatic efficient hydrolysis. Combined use of th
ese prodrugs with a beta-D-glucuronyl-spacer-doxorubicin (HMR1826) accordin
g to an ADEPT strategy restored in vitro the sensibility of a MDR resistant
strain.