The Complex Of Implants’ Materials And PLGA Drug Delivery System

With the clinical requirement for implants increased, it’s important to improve the implanting success rate. There are two reasons for the failure of implant, one is the bacterial infection, and the other is the aseptic loosening caused by poor biological fixation. So in order to improve the implants’ activity of antibacterial and biological immobilized, the combination of drug delivery system and implant becomes a hot spot of research. However, there isn’t a best method to combine DDS and implants, so this thesis is studied on the combination of material and system.Firstly, we prepared poly lactic-co-glycolic acid (PLGA) microspheres by solvent evaporation method. We fixed the microspheres on the inorganic biological materials Titanium and hydroxyapatite (HA) by vacuum drying. The microspheres could fix on the material surfaces stably by SEM and TOC evaluation. We prepared PLGA-GS microspheres by W1/O/W2 and PLGA-DEX microspheres by W/O1/O2. We studied the drug release and activity. The drug release results showed that PLGA-GS microspheres had a burst release, then released slowly, but PLGA-DEX microspheres kept a slow sustained release without burst release. The in vitro antibacterial test and cell culture experiment showed both drug had good activity.Then, we prepared a HA coating on Ti-6Al-4V surface by sol-gel method. The coating was a uniform and compact HA coating by SEM, XRD and FTIR evaluation. We also studied the fixation stability of PLGA microspheres on this material surface. The stability was proved well by SEM and TOC evaluation. PLGA-CIP microspheres were prepared with different molecular weight by W1/O/W2. The molecular weight had remarkable effect on the burst release and no remarkable effect on the sustained release. The burst release was serious, so the method should be studied further. The in vitro antibacterial test showed that PLGA-CIP microspheres had good antibacterial ability.At last, we studied the fixation stability of PLGA microspheres on biomedical polymer material-high density polyethylene (HDPE). The HDPE was surface modified by KMnO4/H2SO4 solution to improve the hydrophily. After modification the water contact angle was decreased from 98° to about 52°. We studied the fixation stability of PLGA microspheres on the HDPE after modification. The results showed the stability was good. In this section, we studied the PLGA-GS microspheres antibacterial activity after soaking in PBS for 1 h,3 h,6 h. The results showed that after soaking, the antibacterial activity couldn’t be observed. So if we want to use PLGA-GS microspheres in a field which needs a long time minimal inhibitory concentration, we should have a further studied of the preparation of PLGA-GS microspheres.