Facile preparation of pH-responsive polyurethane nanocarrier for oral delivery

This study reports a novel one pot synthesis of pH-responsive nanocarrier for oral delivery of hydrophobic drug under gastrointestinal tract.Triblock copolymer MPEG-HTPB-MPEG was synthesized coupling of MPEG and HTPB using hexamethylene diisocyanate(HDI) and pH-responsive carboxylic acid group was attached to polybuthadiene backbone by thiol-ene click reaction in a facile and convenient procedure. The MPEG-HTPB (g-COOH)-MPEG block copolymers were self-organized into micelle assemblies in the-water. The size and shape of the micelle assemblies were confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The nanocarriers have high drug loading ability for poorly water-soluble drug. The pH-responsive profile was demonstrated by pH-dependent swelling and in vitro drug release. <10.0% IBU was released under artificial gastric fluid after 2 h, whereas an immediate release was observed under artificial intestinal fluid. The XTT assay indicated that the micelle obtained from PEG-HTPB (g-COOH)-PEG triblock copolymer are safe in a wide range of concentrations. The results show that pH-responsive PEG-HTPB (g-COOH)-PEG triblock copolymers are promising nanocarriers for the oral administration of hydrophobic drugs. (C) 2016 Elsevier B.V. All rights reserved.