New heparin–indomethacin conjugate with an ester linkage: Synthesis, self aggregation and drug delivery behavior

New heparin–indomethacin conjugate with an ester linkage was prepared by the carbodiimide-mediated condensation reaction, and then characterized by FTIR and 1HNMR analyses. Due to its amphiphilic character, such a conjugate could self-aggregate into spherical nanoparticles in aqueous system, as confirmed by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. By the in vitro drug release tests, the resultant conjugate nanoparticles were found to have a sustained and esterase-sensitive release behavior for conjugated indomethacin. In addition, the uptake of these conjugate nanoparticles into human nasopharyngeal carcinoma CNE1 cells was confirmed by fluorescence microscopy.