Introducing a squaramide-based self-immolative spacer for controlled drug release.

Herein we report the design, synthesis and assessment of the first example of a squaramide-based self-immolative system triggered by an enzymatic reduction. We have proved that the release of the alkylating agent N′,N′-(bis(2-chloroethyl)benzene)-1,4-diamine (ANM) provokes a dramatic reduction of the survival factor in glioblastoma cells, evidencing the suitability of the squaramide-based spacer for drug delivery applications.