Controlled and sustained drug release performance of calcium sulfate cement porous TiO₂ microsphere composites

Calcium sulphate cement (CSC) is widely used as an osteoconductive biomaterial in bone repair and regeneration.

In this study, porous TiO₂ microspheres were added to CSC to achieve a controlled and sustained drug (gentamicin) release.

Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area analysis were conducted to analyse the morphology, phase composition, and surface area of the TiO₂ micro-spheres and composite cements. In addition, the injection time, compressive strength, degradation behaviour, and antibacterial ability of the composite cements were examined during in vitro degradation. Gentamicin release profile was recorded using an ultraviolet spectrophotometer.

The results revealed the excellent drug loading ability of the TiO₂ microspheres. The addition of TiO₂ microspheres improved the injectability and compressive strength of the composite cements, the maximum value of which was achieved at a TiO₂ loading of 5 wt.%. When immersed in simulated body fluid (SBF), the composite cements doped with TiO₂ microspheres were observed to release gentamicin in a stable and sustained manner, especially in the latter stages of in vitro degradation. During degradation, CSC doped with TiO₂ microspheres exhibited a typical apatite-like behaviour. Further, antibacterial analysis showed that CSC doped with TiO₂ microspheres exhibited long-term antibiotic activity.

Thus, as an effective sustained-release formulation material, TiO₂ microspheres show a great potential for application in bone cements.