Octacalcium phosphate as a precursor for the fabrication of composite bioceramics

Abstract

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.