Strategies to prepare polymers with cleavable linkages releasing active agents in acidic media

Abstract

Incorporating labile bonds in chemical structure of polymer yields interesting materials that are responsive to change of environmental stimuli such as change of pH values. Active agents can be conjugated to various polymers through acid-labile linkages, conferring them with a spatiotemporal control over the cleavage and subsequent release of drug, antibacterials agents or corrosion inhibitors. One of key factors influencing release of active agents is the hydrolytic stability of the linkages. We compare hydrolytic kinetics of the acid-cleavable linkages and discuss the effect of structural fine tuning of the molecules on hydrolysis rate. Synthetic routes of various acid-sensitive linkages are discussed in relation with the functional unit available on active substances to be released.