Pesticide Release Substrate Synthesis And Release Rate Determination Study

The paper based on the properties of the polylactide -poly(ethylene glycol)- polylactide(PLA-PEG-PLA) polymers and fomesafen, then studied the preparation of microspheres loaded with fomesafen by using the solvent extraction method. The ideal process was gotten by changing the stirring rate, concentation of emulsifier and composition of polymers. The molecular struture of PLA-PEG-PLA was detected by IR spectrum, and the fomesafen as the part of the microspheres was characterized by Raman spectra,and the result showed that the polymers and the pesticide formed microspheres by physic method. The crystallization structure and melting temperature was characterized by X-ray diffraction analysis and differential scanning calorimetry (DSC). The size and surface of microspheres were analyzed by Scanning electron microscopy and Laser particle sizer. The results showed that 800rmp stirring rate, 2﹪PVA and PEG(Mw=1000) polymers was the optimum process. The release behavior of 9 simples of microspheres were studied by HPLC,which showed two-phase release patterns of microspheres in 50 days. The whole pesticide was released from the microspheres by special method, then the drug content and encapsulation e?ciency was evaluated by HLPC. The results showed that there were obvious differences among these simples. Finally, the 800rmp stirring rate, 2﹪PVA and PEG(Mw=1000) polymers was the optimum process, and we can get prospective release of the pesticide.