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Four different phase compositions of calcium phosphate (CaP) particles were prepared via a solution combustion method. X-ray diffraction (XRD) and Rietveld analysis results revealed that the variations in the nominal Ca/P (molar) ratios were found to provide a favorable control in the different proportions of CaP materials. Bovine serum albumin (BSA) was used as a model protein to study the loading and release behavior. The release profile indicated that the BSA release rates depended on the phase compositions of the CaP particles, and showed an order of TCP-BSA > BCP-1-BSA > BCP-2-BSA > HA-BSA. The results suggested that the BSA protein release rate can be controlled by varying the phase compositions of CaP carriers. Moreover, the release process involved two stages: firstly surface diffusion via ion exchange and secondly intraparticle diffusion. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP), fluorapatite (Fap) and chlorapatite (Clap) were prepared by solution combustion method with further annealing at 800 °C. The characterization and structural features of the synthesized powders were evaluated by the powder X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques. Characterization results from XRD and Rietveld analysis revealed that OH − in the HAP lattice were gradually substituted with the increase of F − and Cl − content and totally substituted at the molar concentration of 0.28 and 0.6, respectively. The results from FI-IR have also confirmed the incorporation of substituted anions in the apatite structure. [ABSTRACT FROM AUTHOR]

The solution combustion method was used to prepare single phase hydroxyapatite (HA), β-tricalcium phosphate (β-TCP) and biphasic calcium phosphates (BCP). The powder samples were synthesized with a Ca/P molar ratio from 1.45 to 1.67, and annealed at different temperatures. These samples have been characterized by XRD and FTIR. The amount and lattice parameters of each phase in these samples were refined by the MAUD program. The results of Rietveld refinement show that a single phase HA is obtained with Ca/P ratio of 1.67 and annealing at 1150°C for 3h, β-TCP is isolated with a Ca/P ratio of 1.5 after annealing at 950°C and remains stable up to 1050°C. Apart from above two extremes a whole range of BCP can be prepared with a favorable control of Ca/P ratios and annealing temperatures. [ABSTRACT FROM AUTHOR]