Local Delivery of Antibiotics Using Hydroxyapatite with Bi-modal Pore Size Distribution
A novel hydroxyapatite (HA-A) was developed and we evaluated the slow release of antibiotic in vitro as well as osteoconduction of the material in vivo. HA-A (4 x 4 mm) was synthesized by mixing HA powder, gelatin, and vegetable oil. The material had a bi-modal pore size distribution, with intragranular (10 nm to 10 µm) and intergranular (100 µm) pores, and porosity of 40 vol%, while a control HA had pore sizes ranging from 50 to 300 µm and identical porosity. In vitro drug release was tested using antibiotics soaked on the HA cylinders using a vacuum system. The mean adsorption efficiency was higher for HA-A than for control and higher levels of antibiotic were released from HA-A. Bone ingrowth into the pores was observed for both materials. Since the novel HA showed both the slower release of antibiotic (nanosize pores) and supported excellent osteoconduction (microsize pores), it could be useful for the treatment of osteomyelitis.
Takashi Nakamura, Kimihiro Yamashita and Masashi Neo
M. Hasegawa et al., "Local Delivery of Antibiotics Using Hydroxyapatite with Bi-modal Pore Size Distribution ", Key Engineering Materials, Vols. 309-311, pp. 949-952, 2006