Preparation Of Mesoporous Apatite Microspheres With Hydrothermal Process And The Study Of Its Drug Release Property

Research on hydroxyl apatite is always an important developingdirection of in the artificial bone material research category because ithas good biocompatibility and biological activity. And it also has goodcharacteristics such as non-toxic, no immune response to human body.It has great application prospect in bone filling, alternative materialsand drug carrier development.Mesoporous material has large pore volume and specific surfacearea characteristic, so it has great application potential. Mesoporoushydroxyl apatite is provided with the advantage of mesoporousmaterial. The research of it can help to find some bone substitutematerial. Except influenced by the specific surface area, mesoporoushydroxyl apatite bioactivity and drug loading character is also linkedwith its form and internal structure. The internal hollow structure ofhollow hydroxyl apatite has good promotion of its drug loadingperformance.The research in this thesis takes calcium carbonate microspheres asits presoma to develop hydroxyl apatite with stable HA. Then usehydrothermal method to turn calcium carbonate into hydroxyl apatitethat is in microspheres HA and with some calcium carbonate in themiddle of it. Put the product into citric acid that pH is6.0to corrode thecalcium carbonate inside the hydroxyl apatite microspheres so that itturns into hollow hydroxyl apatite microspheres. Take vancomycin as amodel to be loaded in the hydroxyl apatite microspheres and thencompare the performance between hollow hydroxyl apatite and thehydroxyl apatite microspheres. Use XRD、FTIR、 TEM、SEM、BET analyticalmethods to analyze the feature, phase and pore structure of hydroxylapatite.To add chitosan as the inducers of crystal HA can help to prepare calcium carbonate with hexahedron and overlapping structure type.However if we use shells as a source of calcium and take the organicmatter as a template, we will get calcium carbonate microspheres.Turn the two different types of calcium carbonate into hydroxyl apatitewith the measure of hydrothermal and then the conclusion is that usethe ball calcium carbonate as the precursor to make hydroxyl apatitecan get a more stable HA. The mesoporous apatite microspheres madeby hydrothermal method have a high crystallinity and is about5μm indiameter. Apatite microspheres mainly apatite nanoparticles of sheetsof structure formation and accumulation of a layer of the gapsbetween the formation of irregular pore structure,Apatite microspheres are mainly accumulated by the sheet thatformatted with apatite nanoparticles. The gap between the sheetsformed in irregular pore structure. The type IV isotherm and type H3hysteresis loop suggested that the pore is mesoporous structure and itsaperture is mainly concentrated in3.8nm. After processing, the hollowhydroxyl apatite keeps the essential feature of hydroxyl apatitemicrospheres. But for the corrosion of the acid between the process,some of the hydroxyl apatite dissolved. Its pore aperture became largerand to be5nm. The drug loading experiment showed that the loadingcapacity of the hollow hydroxyl apatite is higher than the unsettledones. Its loading capacity can reach85.38%, compared with ordinaryones’52.11%. And its loading efficient also be improved. The loadingefficiency of hollow hydroxyl apatite can reach82.78%while theordinary ones’ loading efficiency is only73.64%.