BIODEGRADABLE GENTAMICIN-LOADED CONTROLLED RELEASE IMPLANTS MADE OF BETA-TRICALCIUM PHOSPHATE CERAMICS .2. PREPARATION AND INVITRO EVALUATION OF GENTAMICIN-LOADED CONTROLLED RELEASE PELLETS

Gentamicin-loaded controlled release implants for the local antibiotic treatment of bone infections were prepared and evaluated in vitro. Well defined, porous ceramic pellets of beta-tricalcium phosphate (beta-TCP) were loaded with the broad range antibiotic drug gentamicin sulfate. In order to achieve sustained release of the drug, additional impregnation of the pellets with glycerides was necessary. Different types of glycerides were tested. Homogeneous distribution of the drug in the ceramic pellets also improves the sustained release. Drug release from the implants is influenced by parameters such as drug loading, size and porosity of the ceramic pellets. Depending on these parameters, the gentamicin was released over a period of 2 to 3 weeks in vitro. The release pattern does not strictly follow first order kinetics and can not be described by a square-root of time equation.