Preparation And In Vitro Release Properties Of OPG-PLGA Drug Delivery System

ObjectiveIdeal implant restoration needs long term function of implant and good effect of aesthetic repair,which requires proper sclerotin and bone mass of alveolar bone.In clinical practice,there is a lack of bone resorption after tooth extraction.A large number of studies have confirmed that osteoprotegerin(OPG)can inhibit the maturation and function of osteoclasts,which can block the effect of alveolar bone resorption.In this study,using polylactic acid glycolic acid(PLGA)as carrier,OPG-PLGA sustained-release microspheres were prepared.The optimal preparation conditions were selected and the release characteristics of drug loaded microspheres were studied via investigating the encapsulation efficiency and drug loading of microspheres,in order to provide the basis for the further study and clinical application in the future.Methods1.Using PLGA as a drug carrier,a mixed solution of dichloromethane and acetone(4:1)as organic solvent,and polyvinyl alcohol(PVA)as surfactant,OPG-PLGA microspheres were prepared by double emulsion solvent evaporation method.Drug loading and encapsulation efficiency were determined by ELISA method;2.The loading and encapsulation efficiency of microspheres as the investigation index,to determine the influence factors of different polymer concentration,organic solvent,dosage,PVA concentration and stirring speed on the properties of the microspheres by single factor experiment;3.The optimum preparation conditions were determined by using orthogonal test design and investigating the entrapment efficiency and drug loading.The diameter distribution and appearance of microspheres were observed by particle size analyzer and inverted phase contrast microscope;4.A certain amount of OPG-PLGA sustained-release microspheres were placed in the buffer of PBS,and the release properties of the microspheres were investigated under the condition of constant temperature of 37 ℃.Results1.The results of orthogonal test showed that the drug loaded microspheres with 400 rpm stirring rate,2% PVA concentration and 400mg/ml PLGA concentration had the best drug loading and encapsulation efficiency,which were 75.10% and 6.21*10-7,respectively.Through the particle size analysis and the microscope observation,the microspheres had uniform size distribution,smooth surface and no adhesion.2.In vitro release test showed that the initial release rate of the sustained-release microspheres in vitro was 31.34%,and the cumulative release rate of 30 d was up to 93.12%,which indicated that the OPG-PLGA microspheres had a good effect.Conclusions1.The OPG-PLGA microspheres,prepared by double emulsion solvent evaporation method through the optimal preparation conditions,had good morphology,uniform size,and high encapsulation efficiency and drug loading.2.At the same time,the microspheres had good release characteristics,can maintain the effective drug concentration for a long period of time and long term effective drug concentration.So it can be used as a good osteoprotegerin sustained-release system applied in the follow-up study,and provides a theoretical basis for the clinical application in the extraction of site preservation.