FABRICATION OF POROUS HYDROXYAPATITE CERAMICS FROM HOLLOW SPHERICAL AGGLOMERATES PREPARED BY SPRAY PYROLYSIS
2011 Volume 25 Pages 78-86
Details
2011 Volume 25 Pages 78-86
The fabrication conditions of porous hydroxyapatite (Ca10(PO4)6(OH)2; HAp) ceramics were investigated using the hollow spherical agglomerates prepared by spray pyrolysis. The starting HAp powder prepared by the spray pyrolysis of 0.50 mol·dm-3 calcium nitrate (Ca(NO3)2) and 0.30 mol·dm-3 diammonium hydrogenphosphate ((NH4)2HPO4) solutions at 600°C consisted of hollow spherical agglomerates with diameters ranging from 5 to 15 μm. Prior to firing, the cylindrical compact was fabricated using the HAp powder through the following procedures: (i) the compaction through the "uniaxial pressing" of HAp powder at 20 - 50 MPa, and (ii) the compaction through the "suction filtering" of aqueous slurry containing HAp powder. The resulting HAp compact was fired at a temperature between 1000 and 1300°C for 5 h in air. After firing at 1000°C for 5 h, the maximum porosity of HAp body was 77% (suction filtering technique) › 53% (uniaxial pressing technique). Pore sizes of the porous HAp bodies fabricated using suction filtering were distributed over the range of 1 to 5 μm, and the compressive strength was 1.2 MPa. The releasing behavior of gentamicin sulfate (GEN) loaded on the porous HAp bodies fabricated by firing the suction-filtered compact at 1150°C for 5 h showed that a large amount of GEN was released from the porous HAp body within 1 h in the phosphate buffered saline (i.e., the releasing from the surface of porous HAp body), the reduced releasing in the period of 1 to 7 h, and steady state in the period of 9 h to 14 d (i.e. the releasing of GEN from the insides of HAp body via the intergranular channels).
