Fig. 2. PEG–DEC–Cipro releases ciprofloxacin rapidly and quantitatively after reduction. (a) Chemical structures of PEG–DEC–Cipro, PEG–DCB–Cipro, PEG–DCBMe–Cipro and PEG–DTB–Cipro. (b and c) DEC (blue) releases free ciprofloxacin completely with a t1/2 of 5 minutes in the presence of cellular GSH concentrations (10 mm) at pH 7.4. In contrast, the DTB linker (red) had a t1/2 of 30 minutes and was unable to completely release the free amine and the DCB linker (green) had a t1/2 of 90 minutes. DCBMe linker (purple) has a t1/2 of 15 minutes, which is shorter than the traditional DCB linker.
