Scheme 1. Reaction mechanisms of the mechanochemical and reductive scission of disulfide-centered polymers with adjacent β-carbonate linked drugs and fluorophores that are released by a subsequent 5-exo-trig cyclization. (a) N-Butyl-4-hydroxy-1,8-naphthalimide (NAP) was released in conjunction with camptothecin (CPT) from 1 or P1; (b) umbelliferone (UMB) together with gemcitabine (GEM) from 2 and P2; (c) small molecule 3 and terminally functionalized polymer P3 controls did not lead to UMB release by ultrasonication.
