Reducibly degradable hydrogels of PNIPAM and PDMAEMA: Synthesis,stimulus‐response and drug release

Reducibly degradable hydrogels of poly(N‐isopropylacrylamide) (PNIPAM) and poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) were synthesized by the combination of reversible addition‐fragmentation chain transfer (RAFT) polymerization and click chemistry. The alkyne‐pending copolymer of PNIPAM or PDMAEMA was obtained through RAFT copolymerization of propargyl acrylate with NIPAM or DMAEMA. Bis‐2‐azidyl‐isobutyrylamide of cystamine (AIBCy) was used as the crosslinking reagent to prepare reducibly degradable hydrogels by click chemistry. The hydrogels exhibited temperature or pH stimulus‐responsive behavior in water, with rapid response, high swelling ratio, and reproducible swelling/shrinkage cycles. The loading and release of ceftriaxone sodium proved the feasibility of the hydrogels as the stimulus‐responsive drug delivery system. Furthermore, the presence of disulfide linkage in AIBCy favored the degradation of hydrogels in the reductive environment. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3604–3612, 2010