Cathepsin B-sensitive dipeptide prodrugs. 1. A model study of structural requirements for efficient release of doxorubicin

A series of lysosomal protease-sensitive peptides attached to doxorubicin (DOX) was prepared as model substrates for internalizing anticancer immunoconjugates and potential antimetastasis prodrugs. Rates of cathepsin B-mediated release of free drug was measured for each, and human plasma stabilities for representative examples.