Fabrication Of Magnetic Mesoporous Apatite Microspheres And The Study Of Their Drug Release Profiles

Apatite has been used widely as bone cavity and drug delivery because of their good performance such as bioactivity, biocompatibility, degradation and noninflammatory. The bioactivity, load & release property of biomaterials are related to the chemical compositions, chemical constitution as well as magnetic property and mesoporous of the biomaterials. Magnetic mesoporous apatite microspheres has become the hot spot in the field of biomedical materials. This paper uses calcium carbonate microspheres as precursor, convert to magnetic mesoporous apatite microspheres by hydrothermal method and in-situ templates method. The pattern, microstructure, and pore structure of magnetic mesoporous apatite microspheres were studied by means of FTIR, XRD, SEM, TEM, ICP, BET. Study the drug loading and releasing of magnetic mesoporous apatite microspheres with vancomycin as a model drug. The influence mechanism of meosporous and magnetic nanoparticles on the drug payload and release were also researched.Calcium carbonate microsphers were prepared by using the CaCl₂ solution from nacre as the source of calcium, mixing Na₂CO₃ solution. Carbonate Meosporous apatite microspheres were converted from calcium carbonate microsphers by hydrothermal method. The size of mesoporous apatite microspheres is ⁵μm. The surface of mesoporous apatite microspheres are deposited by flakes or spheres nanoparticles which are high crystallinity. The mesoprous structure are formed by nanoprticles with the pore size of 3.8nm, the nitrogen adsorption-desorption isotherms are type IV isotherms with H3 hysteresis loops. Meosporous apatite microspheres converted by hydrothermal method have good bioactivity and deposit with bone-like apatite after soaking in SBF for 24h. In the drug loading process, meosporous apatite microspheres have drug payload of 30.67³9.64%, the cumulative release in PBS was 73.68⁹6.39% for 20h, which shows good release capacity.Using the Fe₃O₄ nanoparticles, CaCl2 solution from nacre and Na₂CO₃ solution as feeds, magnetic calcium carbonate microsphers were prepared by in-situ coprecipitation. Magnetic mesoporous apatite microspheres were converted by hydrothermal method, study the influence of magnetic nanoparticles on the transformation rate of the microspheres, bioactivity, and drug delivery. The study finds that Fe₃O₄ don't influence the pattern of mesoporous apatite microspheres . The size of magnetic mesoporous apatite microspheres is ⁵um. The pore size of mesoprous structure is ³.8 nm which are deposited with apatite nanoparticles. Fe₃O₄ nano-particles increases the velocity of formation of apatite and bioactivity. In the drug loading process, magnetic meosporous apatite microspheres converted by hydrothermal method have drug payload of 27.24³7.96%, the cumulative release of drug in PBS is 62.89⁷2.11% for 20h. Magnetic mesoporous apatite microspheres have better release capacity than the capacity of mesoporous apatite microspheres converted by the same method.The mesoporous apatite microspheres converted from calcium carbonate microspheres in a cetyltrimethylammonium bromide (CTAB)/Na₂HPO₄ solution/cyclohexane/n-butanol emulsion system by in-situ template based model. Functional microspheres are piled up by apatite nanoparticles. The size of microspheres is ⁵μm. The nitrogen adsorption-desorption isotherms are type IV isotherms with H3 hysteresis loops. Magnetic meosporous apatite microspheres converted by in-situ templates method have good bioactivity, drug payload and release capacity. The magnetic meosporous apatite microspheres have drug payload of 81.77⁸9.85%, the cumulative release in PBS is 51.43⁸3.11% for 20h.