Study on the applied properties of tobramycin-loaded calcium phosphate cement

Calcium Phosphate Cement (CPC), as a kind of novel biomaterials for repairing bone defects, has received much attention from material and medical circles because of its high biocompatibility and self-setting capability, and has become a research focus among current biomaterials. Since CPC is characterized with mildness during the setting process, we introduce tobramycin, a kind of antibiotics drugs commonly used for orthopedics, into the material, to provide an efficient solution for not only the repair but also the treatment of the bone disease in terms of controlled release of the drug. Although many efforts have been made to the study on the kinetics of drug delivery in the drug-loaded system, there is still little systematic research in its applied properties. This paper studies on the applied properties of drug-loaded CPC system, including the setting time, compressive strength, hydrating products and microstructure analysis. The results show that the introduction of the drug has no effect on the hydrating products. And with the rise of the content, the setting time has been delayed, which will bring about some trouble in the operation, so for the clinical application, the content of tobramycin should be below 5%. In the mean while, the compactness of the solidified body decrease, the pore sizes of the hydrating products increases, and the strength drops gradually, which is due to the anti-agglomeration among the CPC particles as a result of the existence of the drug. However, after a week of incubation in the simulated body fluid, the strength of the material will rise and can reach about 36MPa. The compactness of the microstructure will also increase, some of which will form acicular hydrating products. This proves that CPC experiences a process of rehydration in the simulated body fluid, which makes the hydrating products more compacted. All these results may have some guiding significance in the clinical application of this material.