Preparation and characterization of calcium phosphate cement of α-tricalcium phosphate-tetracalcium phosphate-dicalcium phosphate system incorporated with poly(γ-glutamic acid)

Polymeric calcium phosphate cements (PCPCs) were prepared from cement powders consisting of alphatricalcium phosphate (α-TCP), tetracalcium phosphate (TTCP) and dicalcium phosphate (DCP), and cement liquid with poly(γ-glutamic acid) (γ-PGA). The characteristics of calcium phosphate cements (CPCs), such as paste injectability, initial setting time, and compressive strength, were assessed. The injectability of PCPCs with a 0-30 wt% TTCP/DCP mixture was above 90%. The initial setting time decreased in concert with the amount of incorporated TTCP/DCP mixture and reached approximately 10-13 min when the amount of TTCP/DCP mixture was 10-30 wt%. The compressive strength of PCPC with the 30% equimolar TTCP/DCP mixture was approximately 18.4±3.5 MPa, whereas that of the CPC without the TTCP/DCP mixture was approximately 4.8±0.1 MPa.