RESUMEN
BACKGROUND:Cycloserine with low hepatotoxicity exhibits no cross-resistance with the existing anti-tuberculosis drugs,and has been commonly used for the treatment of drug-resistant tuberculosis.However,its oral administration or injection leads to a certain degree of neurotoxicity.OBJECTIVE:To prepare poly(lactic-co-glycolic acid) (PLGA)-cycloserine sustained-release microspheres which are expected to reduce the neurotoxicity and adverse reactions,and maintain the drug concentration in the bone tuberculosis region for a long time,and to observe the in vitro drug release of the microspheresMETHODS:Double emulsion solvent evaporation method was used to prepare PLGA-cycloserine microspheres that were bonded into sponge implant by Bletilla striata polysaccharide extract.Then,morphology,particle size,encapsulation efficiency and in vitro performance of the microspheres were observed.The drug loading,burst release,appearance and dispersion of the microspheres were observed at 0,1,2 months after the microspheres were placed in room temperature (25 ℃),high temperature (60 ℃) and high humidity (93％),respectively.RESULTS AND CONCLUSION:The PLGA-cycloserine microspheres that were round and spherical presented with the mean particle size of (143±38) μm,the drug loading of 38.38％ and the encapsulation efficiency of 67.54％.No burst release occurred,and the cumulative release of drug within 50 days was 65.62％ After being stored at room temperature,high temperature and high humidity for 1 and 2 months,the microspheres were intact in the appearance and morphology,and showed insignificant changes in drug loading and burst release.To conclude,the time of degradation and the release of drug accord with the biological requirements of bone restoration.