Preparation and Characterisation of Hydroxyapatite and Carbonate Substituted Hydroxyapatite Granules

摘要

Phase pure hydroxyapatite and a high purity mixed AB-type carbonate substituted hydroxyapatite (CHA) were synthesised by precipitation reactions. The CHA was produced in the absence of sodium and ammonium ions which are normally introduced into the precipitation reaction to maintain charge balance (1,2). Both the HA and CHA filter cakes were processed into granules of three different size ranges (212-500#mu#m, 500#mu#-1mm, l-2mm). The granules were sintered and underwent full structural characterisation. Both sets of granules exhibited similar morphologies and were acicular in shape. The apparent density (97-98 percent) and the packing densities of the two sets of granules were similar (50-55 percent). Comparable packing densities are important for in-vivo studies since this allows direct comparison of chemical effects when the same mass of granules can be implanted into a standard volume implant site. In this study we have seen granules of HA and CHA produced which have similar physical properties with the only difference being the effect of carbonate substitution in CHA. This paper reports the production and the physical and chemical characterisation of high purity HA and CHA granules as a precursor step in the development of a suitable in-vivo model