RESUMEN
BACKGROUND: Anti-tuberculous chemotherapy is the main method for treating bone and joint tuberculosis. However, systemic administration hardly maintains the effective drug concentration in the focus area, and the therapeutic efficacy is unsatisfactory. OBJECTIVE: To prepare a chitosan-gelatin/poly(lactic-co-glycolic acid) combined with drug-loaded hydrogel, which can release anti-tuberculosis drugs in situ for a long time and promote osteogenesis. METHODS: Isoniazid, a hydrophilic anti-tuberculosis drug, and a hydrophobic stromal cell derived factor-1 were loaded into poly(lactic-co-glycolic acid) by double emulsion method to prepare drug-loaded poly(lactic acid co-glycolic acid) microspheres, which were then mixed into chitosan gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogel. The ability of drug delivery and anti-tuberculosis of poly(lactic acid co-glycolic acid) microspheres and chitosan gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogels in vitro were tested. MC3T3-E1 cells were inoculated on the surface of microspheres and hydrogel respectively. The biocompatibility was detected by cell counting kit-8 assay. The osteogenetic activity was detected by alkaline phosphatase activity. RESULTS AND CONCLUSION: (1) The burst release of isoniazid in the microspheres was about 23.3% in 1 hour, 42.6% in 2 days, and then it entered the sustained-release stage in the later 25 days. The burst release of stromal cell derived factor was about 19.8% in 1 hour, 44.7% in 2 days, and then it entered the sustained-release stage in the next 25 days. The release of isoniazid and stromal cell-derived factor in the combined drug-loaded hydrogel was 8.3% and 8.5% in the first hour, respectively. The cumulative release rates on the second day were 15.2% and 17.6%, respectively, which were much lower than that of poly(lactic acid co-glycolic acid) microspheres. (2) After 4 weeks in vitro, the antibacterial diameter of the combined drug-loaded hydrogel was much larger than that of the drug-loaded microspheres, and the antibacterial rate was higher than that of the drug-loaded microspheres (P < 0.05). (3) The combined drug-loaded hydrogel and the drug-loaded microspheres had good cytocompatibility and cell viability was about 100%. (4) After 5 and 10 days of culture, there was no significant difference in the activity of alkaline phosphatase on the surface of drug-loaded hydrogel and drug-loaded microspheres. (5) These results show that the in situ chitosan-gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogel can be used for treating tuberculosis and other bone and joint infections.
RESUMEN
OBJECTIVE:To prepare the gene recombined human interferon-alpha poly(lactic acid-co-glycolic)microspheres and study its physicochemical properties.METHODS:Interferon-? microspheres were prepared by W/O/W solvent extraction technique;the in vitro release of microspheres were examined;the rudimental organic solvent was determined with GC-MS.RESULTS:The IFN-?-MS were regular in their morphology,and the particle size distribution was narrow.The average diameter was 45.54?m.The encapsulation rate and the loading efficiency were 83.49% and 8.03%,and the in vitro accumulative release rate was 80.32% in 30 days.The in vitro interferon-? release from the microspheres was best described using Higuchi diffusion model.The rudimental of dichloromethane was less than 0.05%.CONCLUSIONS:The prepared IFN-?-MS is very good in all aspects of its physicochemical properties.