Analysis of physicochemical properties of octacalcium phosphate prepared by hydrolysis and co-precipitation with fluoride ions

The present study was designed to determine the physicochemical properties of octacalcium phosphate (OCP) and its products obtained by different preparations in the presence of fluoride ions (F^-) through hydrolysis of the synthesized OCP and coprecipitation. X-ray diffraction and chemical analyses of the products showed that OCP tended to be hydrolyzed into an apatitic structure in both preparations, while the OCP structure remained when hydrolyzed in alkaline pH and obtained by coprecipitation. The solubility decreased with increasing the F^- content in the hydrolyzed products but almost corresponded to that of the original OCP in the co-precipitation products. The results confirmed that the different preparation produces OCP hydrolyzates having distinct physicochemical properties that preserve the characteristics of OCP to some extent. Analysis of cytochrome c (used as a model protein of growth factors) adsorption onto the crystals indicated that the hydrolysis groups had the highest capacity to adsorb.