"Synthetic hydroxyapatite (HAp, (Ca₁₀(PO₄)₆(OH)₂) has always been of interest in medical applications because of its similarities to inorganic bone matrix. It has been used in biomedical applications for bone repair and substitution due to its biocompatibility. However, there are some differences in the stoichiometry, composition, and mechanical properties of human bone as compared to pure HAP. HAp particles have been successfully used as drug delivery carriers which deliver the drug to the affected part of the body and the remaining apatite gets degraded by the physiological processes in the body. In the present work, emphasis was on developing mechanically stronger HAp microspheres. Calcium lithium borate glass microspheres with 40 wt% calcium were reacted with phosphate (K₂HPO₄) buffered solutions under varying conditions of composition of glass, time, concentration, and pH to yield solid but porous HAp microspheres. DOE approach was used to analyze the effect of processing parameters on the reaction rate. The starting glass microspheres had diameters ranging from 150 to 355 µm and the reacted microspheres retained their shape and size. The microstructures of the reacted microspheres were examined using scanning electron microscopy (SEM). Chemical characterization of the reacted microspheres was also performed by X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS), and Differential Thermal Analysis (DTA) studies. The as-reacted HAp microspheres were heat-treated at various temperatures which resulted in volume shrinkage of the microspheres and attributed to reduction in the porosity. Mechanical strength of as-reacted microspheres and heat-treated microspheres was tested by compressive load on an Instron Testing machine. The as-reacted microspheres had higher strength than as-reacted hollow HAp microspheres"--Abstract, page iii.
Okafor, A. Chukwujekwu (Anthony Chukwujekwu)
Henthorn, Kimberly H.
Dharani, Lokeswarappa R.
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
Missouri University of Science and Technology. Center for Bone and Tissue Repair and Regeneration
Missouri University of Science and Technology
xii, 92 pages
© 2010 Gurpartap Singh Sandhu, All rights reserved.
Thesis - Open Access
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Sandhu, Gurpartap Singh, "Synthesis and characterization of microspheres for controlled release" (2010). Masters Theses. 6937.