Mechanical Strength and Drug Release Characteristics of Bioactive Bone Cement Using α-Tricalcium Phosphate and Biopolymer

New bioactive bone cement was developed using α-tricalcium phosphate as bioactive powder and poly (sodium-glutamate) (PSG), bovine serum albumin (BSA) and malic acid as additives. The performance of cements was evaluated in terms of the compression strength and the drug release rate. The compression strength increased with the amount of additives, and became larger in order of malic acid, BSA and PSG with the same amount of additives. The maximum strength was obtained when PSG was used because of the heat denaturation of PSG and the conversion from PSG to polyglutamic acid. The maximum strength was almost equal to that of polymethylmethacrylate cement (about 68MPa). The drug release process was solved numerically by the diffusion equation for cylindrical pellets. The apparent diffusion coefficient decreased with increase in the amount of additives, and became smaller in order of malic acid, BSA and PSG with the same amount of additives.