Preparation of starch nanoparticles in water in oil microemulsion system and their drug delivery properties

In this research, 1-hexadecy1-3-methylimidazolium bromide C(16)mimBr/butan-1-ol/cyclohexane/water ionic liquid microemulsion was prepared. The effects of n-alkyl alcohols, alkanes, water content and temperature on the properties of microemulsion were studied by dilution experiment. The microregion of microemulsion was identified by pseudo-ternary phase diagram and conductivity measurement. Then starch nanoparticles were prepared by water in oil (W/O) microemulsion-cross-linking methods with C(16)mimBr as surfactant. Starch nanoparticles with a mean diameter of 94.3 nm and narrow size distribution (SD = 3.3) were confirmed by dynamic light scattering (DLS). Scanning electron microscope (SEM) data revealed that starch nanoparticles were spherical granules with the size about 60 nm. Moreover the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) demonstrated the formation of cross-linking bonds in starch molecules. Finally, the drug loading and releasing properties of starch nanoparticles were investigated with methylene blue (MB) as drug model. This work may provide an efficient pathway to synthesis starch nanoparticles. (C) 2015 Elsevier Ltd. All rights reserved.