Alginic acid-based pH and thermo responsive reversible switched polymeric micelle via RAFT polymerization

Amphiphilic copolymers derived from natural polymers have drawn significant interest as hydrophobic drug carriers owing to their hydrophobic core and hydrophilic exterior shell. In this context, a new amphiphilic copolymer, Alg-g-PNIPAAm, was synthesized by inserting thermoresponsive N-isopropylacrylamide (NIPAAm) on an alginate-modified macro-RAFT reagent (Alg-DSCPA) through the reversible addition fragmentation chain transfer (RAFT) technique. Alg-g-PNIPAAm has shown stimuli-responsive (pH and temperature) reversible micellization behavior, which permits controlled micelle formation as well as phase separation. Dipyridamole (DP), a model hydrophobic drug, has been encapsulated on micelles via hydrophobic interactions. The drug loading was found to be ∼37 %, while the encapsulation efficiency was found to be ∼75 %. The DP-loaded micelles revealed pH- and thermoresponsive release patterns with enhanced therapeutic efficacy. Additionally, the copolymer has been found to be noncytotoxic against HEK293T, HeLa and HCT116 cells lines, which enhanced its applicability in the field of drug delivery.