Effects of neutral sodium hydrogen phosphate on setting property and hemostatic ability of hydroxyapatite putty as a local hemostatic agent for bone

We have previously reported that hydroxyapatite (HAP) putty had good hemostatic ability and showed excellent biocompatibility. Although the setting reaction of HAP putty and resulting transformation to HAP are the causes of excellent biocompatibility, it allows us limited handling period. In this study, relationship between the setting reaction of HAP putty and hemostatic ability were investigated using the neutral sodium hydrogen phosphate concentration and time after preparation as an index. We found larger concentration of neutral sodium hydrogen phosphate resulted in the decreased hemostatic ability. Hemostatic ability of HAP putty decreased with time after its preparation. However, hemostatic ability was much better when HAP putty was used within 10 min after preparation. Adhesion of HAP putty to bone increased with time, and thus rebleeding was inhibited in the case of HAP putty. Although the limited handling time is a drawback of HAP putty, we feel HAP putty has good potential value as a hemostatic agent since it has high reliable hemostatic ability with excellent biocompatibility.