Fabrication And Properties Of Drug-loaded Poly(Lactic-co-glycolic Acid)(PLGA) Microspheres By Coaxial Electrospray

Osteosarcoma is a malignant bone tumor developed from the human stromal cell line and usually occurs in people under 20 years of age.It is the most common bone malignant tumor in children,which is about 5%of the children's tumor.At present,osteosarcoma still accounts for a high proportion of the mortality of malignant tumors in children and adolescents.The combination therapy of adjuvant chemotherapy and postoperative consolidation chemotherapy or radiation therapy before tumor resection is very important for controlling tumor metastasis and improving survival rate.Microspheres,as a drug delivery system that has been extensively studied in recent years,have solved the disadvantages of the small molecule drugs'poor pharmacokinetics and systemic toxicity.This drug controlled release system,mediated by microspheres?MPs?,has been widely used in adjuvant therapy in recent years.There are many carrier materials for the preparation of microspheres,which are mainly divided into natural organic polymer microspheres,such as sodium alginate microspheres,cellulose microspheres,silk fibroin microspheres,Rana chensinensis skin collagen microspheres,etc.,and synthetic organic polymer microspheres.?such as polylactic acid microspheres?.In this study,the biodegradable polymer polylactic-glycolic acid copolymer?PLGA?was used to prepare the drug loaded microspheres with shell structure.The morphology,internal structure,drug loading rate,entrapment efficiency,drug release,microsphere degradation and cytotoxicity of the prepared microspheres were characterized and analyzed.In this study,two kinds of drug loaded microspheres were prepared by electrostatic injection.They are paclitaxel and etoposide-loaded Poly?lactic-co-glycolic acid?microspheres and adriamycin and vincristine-loaded PLGA magnetic microspheres with targeted action.Preparation and properties of PLGA microspheres containing paclitaxel etoposide.Three kinds of microspheres containing different drugs,such as PLGA/P,PLGA/E and PLGA/PE,were prepared by electrostatic injection.They had smooth surface,uniform particle size,obvious putamen structure and good dispersibility.The size and apparent morphology of microspheres did not change significantly with the different kinds of drugs.The average particle size was about 3?m.The microspheres loaded with PTX and ETP showed less obvious burst release than the microspheres loaded alone,showing two sequential drug controlled release mechanisms.The cytotoxicity of microspheres was detected by CCK-8 kit.The results showed that the toxic side effect of PTX microspheres combined with ETP on osteosarcoma was more obvious than that of single drug.It is proved that the drug loaded microspheres with core shell structure prepared by electrostatic spraying have predictable medical prospect in the combination therapy for osteosarcoma,and have a potentiality in the treatment of osteosarcoma.Preparation and properties of adriamycin and vincristine-loaded PLGA magnetic microspheres.Preparation of Fe₃O₄ magnetic nanoparticles by co precipitation method,uniform spherical nanoparticles.The Fe₃O₄@?P+V?/D,Fe₃O₄@?P+D?/V,Fe₃O₄@P/?V+D?microspheres were prepared by electrostatic injection.The surface microspheres were smooth,dispersive,and had good targeting effect.The particle size of this system is small but its range is wide.The average particle size was between 0.32?m and 0.79?m.The particle size distribution changed obviously with the different ways of adding medicine.In the test of encapsulation efficiency,the drug encapsulation rate of drug and carrier material at the same level is higher.In the degradation experiment,with the increase of time,circular pores appeared gradually,which accelerated the degradation.Compared with the first microsphere system without magnetic nanoparticles,the degradation rate increased significantly.In this system,the magnetic microspheres were characterized by bioactivity.The osteosarcoma cells were treated with drug treatment 24H and 48H,and were characterized by CCK-8 kit and dead cell staining.The results showed that the cytotoxicity of Fe₃O₄@?P+V?/D,Fe₃O₄@?P+D?/V,Fe₃O₄@P/?V+D?microspheres decreased in turn.The PLGA magnetic microspheres without drug loading have almost no side effects.Therefore,the drug loaded microspheres prepared with Fe₃O₄ as magnetic targeting particles have good targeting effect and killing effect on osteosarcoma cell lines,and can be used as an ideal treatment for postoperative adjuvant therapy of osteosarcoma.