The diblock copolymer, PEG-b-PMEA, was synthesized by reversible-addition fragmentation chain transfer polymerization (RAFT). The PMEA block contained a polymethacrylamide backbone and twin ortho ester rings in the side-chains. At neutral pH, PEG-b-PMEA self-assembled to form stable micelles. At pH 5, the twin ortho ester rings were quickly hydrolyzed to completion in 12 h, and releasing nearly 70% of the encapsulated Nile Red dye. The PEG-b-PMEA micelles were completely nontoxic to cultured cells as determined by the MTT assay. Paclitaxel (PTX)-loaded micelles showed toxicity toward lung cancer cells comparable to that of the free PTX at equivalent doses. These results suggest that the PEG-b-PMEA micelles could be useful nano-carriers for pH-responsive delivery of poorly soluble anticancer drugs.
Keywords: acid-labile; drug delivery; micelles; ortho ester.
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.