Octacalcium phosphate as a precursor for the fabrication of composite bioceramics.

We have studied the formation of octacalcium phosphate (OCP) in various buffer solutions. Brushite hydrolysis in acetate and succinate buffer solutions at 60°C and pH 5.75 ensures rapid synthesis of pure OCP and substituted OCP (sOCP), which allows a rather large amount of this phosphate (at least 10 g in a single synthesis run) to be obtained in 50-60 min. The observed differences in phase composition between the OCP and sOCP thermolysis products make it possible to obtain biphasic ceramic composites of various kinds: β-TCP/β-CPP (Ca/P = 1.33) in the case of OCP and β-TCP/HA (Ca/P = 1.54) in the case of sOCP. Ceramics with a density of 80% of theoretical density and higher produced using the OCP precursors synthesized in this study have a uniform microstructure, possess the desired microporosity, and are potentially attractive for further advances in the field of bioresorbable osteoplastic materials. [ABSTRACT FROM AUTHOR]