Synthesis of calcium phosphates and porous hydroxyapatite beads prepared by emulsion method

Raw calcium phosphates were synthesized via a chemical reaction between 0.5 M orthophosphoric acid and 0.5 M calcium hydroxide. Hydroxyapatite (HAp), β-tricalcium phosphate (β-TCP) or biphase calcium phosphate (BCP) comprising HAp and β-TCP were obtained by changing pH value, Ca/P ratio, and the addition of glycerol. The as-synthesized and heat-treated powders were analyzed by X-ray diffraction (XRD) and Fourier transformation infrared spectrometry (FTIR). Thermal stability of the pure apatite phase was obtained to be 1300 °C, while synthesis was done at the pH value of 10.0 with a Ca/P ratio of 2.0 and a temperature of 37 °C. Besides, the β-TCP phase (with higher purity) was achieved at 800 °C, whose synthesis was done at pH 6.4 with a Ca/P ratio of 1.5 and a temperature of 37 °C. Therefore, the biphase bioceramics comprising of HAp and β-TCP could be obtained, since it was manipulated suitably. The HAp raw material was subjected to a simple emulsion method for the preparation of porous beads. They should have the advantage of exhibiting higher adsorptive ability and osteoconductivity in comparison with the sintered dense apatite. Additionally, the porous beads of apatite were demonstrated to be non-toxic to cells, and should be suitable for the use as a scaffold of cultured bone and bone graft material, as well as for drug delivery systems.