Impact of hydrogenation on physicochemical and biomedical properties of pH-sensitive PMAA- b -HTPB- b -PMAA triblock copolymer drug carriers

Abstract

pH-Sensitive poly(methacrylic acid)-block-hydroxyl-terminated polybutadiene-block-poly(methacrylic acid) (PMAA-b-HTPB-b-PMAA) was synthesized and then hydrogenated in this work. The chain structure, phase behavior and thermal properties were characterized by ¹H NMR, FTIR, XRD, DSC, TGA, etc., and the physicochemical and biomedical properties were investigated via fluorescence spectroscopy, TEM, DLS, loading and release of drug and MTT, and so on. The experimental results indicated that the hydrogenation led to the change in the chain aggregate structure of hydrophobic HTPB blocks and the formation of more stable spherical core-shell micelle aggregates, and the critical micelle concentration decreased from 41.8 mg L⁻¹ before hydrogenation to 4.4 mg L⁻¹ after hydrogenation. The hydrogenated block copolymer micelle aggregates exhibited pH-triggered response, and could entrap twice as much hydrophobic drug as the unhydrided counterparts and the encapsulation efficiency was significantly improved, which makes them fine to meet the requirements for drug carriers. Therefore, the hydrogenated PMAA-b-HTPB-b-PMAA copolymer micelles as drug target release carriers can be well used in the field of prevention and treatment of cancers.