| abstract |
Disclosed are compounds of formula V-(W)k-(X)l-A-Z, as prodrugs for use in selectively delivering therapeutic agents to target sites,wherein: V is a specifier which is removed by an enzyme, optionally after prior binding to a receptor, (W)k-(X)l-A is an elongated self-eliminating spacer system, W and X are each independently a 1,(4+2n) electronic cascade spacer, A is either a spacer group of formula (Y)m, wherein Y is a 1,(4 +2n) electronic cascade spacer, or a group of formula U being a cyclisation elimination spacer, Z is a therapeutic or diagnostic moiety, k and l are independently an integer from 0 to 5, m is an integer from to to 5, n is a integer of 0 to 10, and k + l > 0. |