Preparation Of Ionic Liquid Microemulsions And The Application In Synthesizing Starch Nanoparticles

Room-temperature ionic liquids（ILs） can replace polar phase, nonphase or surfactant of conventional microemulsion to build IL-based microemulsion. Starch nanopaticles, the particle size ranging from 1 to 1000 nm, is one kind of starch derivatives prepared by cross-linking reaction of starch and cross linking agent. They possess high colloid stability,adsorption performance. In our study, starch nanopaticles were synthesized in ionic liquid microemulsions system. Owing to the preparation of starch nanopaticles was achieved in microreactor of microemulsions, so the size of starch nanopaticles could be controlled by changing the size of microemulsion droplets.On one hand, two ILs, [Omim]Tf₂N and [C₁₆mim]Br, were used in the microemulsion as substitutes for nonpolar phase and surfactant to prepare water/[C₁₆mim]Br + n-butyl alcohol/[Omim]Tf₂N ionic liquid microemulsions. On the other hand, a new room-temperature ionic liquid [C₃OHmim]Ac, based on imidazolium cation that contains additional functional group was synthesized to dissolve starch, and molecular structure was confirmed by FTIR, 1HNMR and ESI-MS. [C₃OHmim]Ac acted as polar phase to prepare[C₃OHmim]Ac/TX-100+ butan-1-ol/ cyclohexane nonaqueous ionic liquid microemulsions.Also, we had learned the properties of those two microemulsions by phase behavior,conductivity measurement and dynamic light scattering（DLS）.Starch nanoparticles were prepared in the W/IL and W/O microemulsions with epichlorohydrin as cross-linker. the characteristics of starch nanoparticles were studied by Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, scanning electron microscope（SEM） and DLS. FTIR data demonstrated the formation of crosslinking bonds in starch molecules; the spectrum of XRD suggested that the crystal structure of starch was destroyed and the intermolecular forces of molecular chains and the hydrogen bond became weak; SEM and DLS both intuitively revealed that starch nanoparticles had good sphericity,small size and a relatively concentrated size distribution.The effect of loading time, loading temperature and drug concentration on drug loading property of starch nanoparticles was sdutied with indoment hacin as the drugs. The results indicated that drug loading and encapsulation efficiency increased firstly, then reduced gradually after reaching a peak value with the prolong of loading time and the rise of loading temperature. With the increase of drug concentration, drug loading efficiency increased, bu encapsulation decreased continuously. The release curve of drug-loaded starch nanoparticles contained three phases: an initial burst release phase, a slow release phase and a sustained release phase.