Synthesis and characterization of calcium deficient apatite granules for drug eluting bone graft applications

Antibiotic loaded calcium deficient apatite (CDA) granules were prepared by wet chemical synthesis followed by microwave irradiation. Microporous CDA granules were loaded with three broad spectrum antibiotics (Amoxicillin, Gentamicin and Chloramphenicol). The aim of this study was to evaluate the in-vitro performance of locally released antibiotics which has a potential to treat infected osseous defects. In-vitro studies of the synthesized material elucidated high drug loading capacity and a drug release profile spanning a period of more than 24 h. The respective antibiotic functional groups were analyzed by Fourier Transform Infrared Spectroscopy (FT-IR). X-ray Diffraction (XRD) was used to study the phase purity of synthesized CDA. Drug release profiles were determined by using UV–vis Spectroscopy. Scanning Electron Microscopy (SEM) was used to investigate granule sizes and porosity. Particle size (2–20 µm) with an average pore diameter of 2.9 µm (±0.5 µm) was achieved without heat-treatment and use of any porogens. Thermal stability was determined using simultaneous Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The drug release profile showed initial burst release followed by sustained release periodically.