Star-shaped amphiphilic block polyurethane with pentaerythritol core for a hydrophobic drug delivery carrier

To obtain polyurethane micelles with excellent stability as a drug delivery carrier, star-shaped amphiphilic block polyurethane (SAPU) was successfully synthesized by the arm-first' method, using methoxypoly(ethylene glycol) and poly(epsilon-caprolactone) diol as soft segments, hexamethylene diisocyanate as hard segments and pentaerythritol as the core. The structure of the SAPU was characterized by Fourier transform infrared spectroscopy, H-1 NMR spectroscopy and gel permeation chromatography. The micellization behaviour and micelle properties of SAPU were measured by the pyrene fluorescence probe technique, H-1 NMR, SEM and dynamic light scattering. The results indicated that SAPU could self-assemble to form nanomicelles in aqueous solution and that the micelles showed excellent stability upon dilution and storage. Indometacin as a model drug could be incorporated into SAPU micelles and be released sustainedly. Meanwhile, the hydrophilic segment content and the molecular weight of SAPU had effects on the micelle properties. In addition, SAPU exhibited good cytocompatibility estimated by methylthiazole-tetrazolium assay. (c) 2016 Society of Chemical Industry