The two novel prodrugs 4 and 11 have been prepared from tetra-O-acetyl
-D-galactopyranose and doxorubicin in three and six steps, respectivel
y. Their low cytotoxicity, high stability in plasma and, in the case o
f 11, efficient hydrolysis in the presence of alpha-galactosidase, ful
fill preliminary conditions for their use in combination with monoclon
al antibody-enzyme conjugates.