Synthesis and characterization of metal ions containing hydroxyapatite microparticles with high specific surface area.

Zinc and/or iron ions containing hydroxyapatite (HA) microparticles, which had twice as high specific surface area and higher pore volumes compared with the pure HA, were fabricated by a spray drying method; the zinc and/or iron ions were incorporated into the constitutional nanocrystals with below 20 nm in size in preparing. The small amount of carbonate ions was substituted in the phosphate group. The particle sizes were distributed in the range of 1 to 20 microm in diameter and its averaged size was approximately 6 microm. The microparticles with a spherical shape showed a single phase of HA and, after treated at higher temperature than 800 degrees C, had the high crystallite HA and the other phase of metal oxide such as ZnO or Fe2O3. The microparticles with higher specific surface area will be applicable for the drug delivery carriers of proteins.