Prepare and release of the chitosan sustained-release drug microspheres

The experimentation used composite crosslinker (formaldehyde and glutaraldehyde) to prepare tetracycline hydrochloridel chitosan sustained-release microspheres by emulsion cross-linking method. In order to select the optimum technology for preparing chitosan sustained-release microspheres,the influencing factors of drug-carried microspheres were analysed,including the types of chitosan,the mass ratio of raw materials,the dosage of crosslinking agent and the emulsifying speeds. Moreover,the experimentation researched the modality of microspheres by scanning electron microscope and chatelier-type microscope.And the in-vitro release characteristics of microspheres were investigated under the conditions of pH=7.4 and temperature is 37℃. The results suggest that prepared with emulsion cross-linking method in this test, the sphericity of microspheres was good, the diameter of microspheres was from 5-50μm. The drugloading was 26.9%, and the enbedding ratio was 56.3%, and the in vitro release of tetracycline hydrochloridel from the microspheres is sustained.