[Biodegradable gentamicin-depot implants made of beta-tricalcium phosphate ceramics. 3. In vivo studies on drug...

In vivo drug release properties and biocompatibility of gentamicin-loaded controlled release implants made of beta-tricalcium phosphate ceramics designed for the local antibiotic treatment of bone infections were investigated. Controlled release pellets containing 0.4 and 0.8 mg of gentamicin were implanted into the femoral bone of rats. Drug release was measured from renal excretion over a time period of 3 weeks. The excretion pattern can be described by an initial phase of increased drug release was faster at higher drug loading. Drug release from glyceride-containing controlled release pellets occurs at a significantly slower rate than from drug-loaded pellets without glycerides. Histological studies after implantation of the pure ceramic pellets and the controlled release pellets into the bone tissue of rats and rabbits are showing a high tissue tolerance and the biodegradability of the implants. However, the glyceride-containing pellets are degraded at a slower rate than the pure ceramic pellets.