Injectable In Situ Solidified Bone Graft Material Loaded With Antibiotics

Calcium Sulfate, as a restore material, shows biocompatibility, biodegradability, osteoconductivity and mechanical property. So the study about using Calcium Sulfate as repairing fillers for the treatment of bone defection is reported now and then, but the injectable property has not been studied so much. When Calcium Sulfate is mixed with water or solution, it becomes an injectable paste. We use Hemihydrate Calcium Sulfate(HCS)as the basic material, compound with Dehydrate Calcium Sulfate (DCS), cellulose and PEG. We have studied the in vitro degradation of the material and interfused antibiotic drugs in it to fabricate an injectable in situ solidified bone graft material.We used secondary treatment method to fabricate HCS from DCS, and studied them by IR, X-ray diffraction and SEM. DCS was modified by PEG to accelerate the solidification of the material. Cellulose can improve the injectability and the mechanical property of the material. The compressive stress test and the SEM analysis showed that the material has excellent properties.The material has appropriate degradation time in PBS, and the maximum water absorption is related with the water content in the material. Throughout the degradation process, the material can maintain the shape all the time.The additive of antibiotic drugs, such as Gentamicin, Norvancomycin and Cefalexin, can affect the crystal structure and the mechanical property of the materials. Because of the nature difference among the three drugs, the release time of the drugs from the carrier was also different. Initially, the drug release was quicker, and then it maintained a certain concentration. We can control the drug release pattern by using sodium alginate and sponge simulant environment.