Objective:Preparation of superparamagnetic sulfate streptomycin PLA-PEG microspheres(spSPM)

and try to establish of an accurate

convenient and effective detection method of high performance liquid chromatography(HPLC) about streptomycin sulfate(SM);to research the properties of this microspheres

and study the laws of drug release under oscillating magnetic field interfered in vitro.This will provide a theoretical basis for our animal experiments and clinical application in the future.Methods:Using chemical coprecipitation to synthesize superparamagnetic chitosan Fe3O4 nanospheres(spCFN)

and then using complex emulsification(W/O/W) to prepare spSPM;put spSPM in simulated body fluid at 37℃

oscillating magnetic field interferes and use HPLC to detect the release of SM.Results:The entrapment rate of this spSPM is 47.56%±1.39%

it

s drug-loading rate is 25.20%±1.52%

the volume averaging particle size is 2.467μm

the cycle of this drug delivery system is more than seven days.Conclusion:The spSPM prepared by this method has all characteristics of the stealh microspheres

and oscillating magnetic field can increase the dissolution of this system repeatability

thus it can be used in further studies.