Poly Lactic Acid Loaded Microspheres Preparation, Characterization And In Vitro Release Performance

Polylactic acid microspheres containing gentamycin sulfate(GTMS-PLA-MS) were prepared by an in-water drying method using a w/o/w emulsion. The comparisons between the two different microspheres were also made. It showed that the two kinds of GTMS-PLA-MS were both spherical in shape and porous in nature through scanning electron micrograph. The particle sizes of GTMS-PLA-MS were analyzed and the average sizes of the two different microspheres were 6.67μ m and 11.70μm, respectively. The encapsulation efficiencies were 37.52% and 49.19%. The drug loading were 25.13% and 39.25%, respectively. It was also proved that GTMS-PLA-MS contained the characteristic peaks of gentamycin sulfate and polylactic acid by FT-IR. The thermal behavior by differential thermal analysis indicated that gentamycin sulfate and PLA mingled each other. The determination of its release rate in vitro revealed it was in sustained release except an abrupt release in the initial 20 minutes. Its comultive release percentage in vitro was over 95%.Based on polylactic acid being an excellent carrier, Rifampicin-polylactic acid-microspheres (RFP-PLA-MS) were prepared by a solvent vaporation method in the experiment. The structure and its properties were characterized by means of SEM, DTA and UV. The comparisons between the two kinds of RFP-PLA-MS(the relative molecular weight of PLA is 25 000 and 100 000 respectively) were carried out. The experiments revealed that the RFP-PLA-MS were regular in its morphology with pores and slots on their surfaces, which provided some channels of the rifampicin from RFP-PLA-MS. The mean diameters of the RFP-PLA-MS were convergence. The encapsulation efficiencies were 7.1% and 5.4%, respectively. And the drug loading was more than 19%. The release in vitro remained slowly.Hydroxyapatites with nature-bone materials' structure, they were low bending intensity and high brittleness. And HA beared bad mechanics performance. Based on bimimetic principle, composites can conquer the shortcoming of the single materials and exert the advantage of the single materials. The composites would have the...