The aim of our project is to develop resorbable nanostructured composite layer with controlled elution of antibiotics for implants survival rate enhancement. The nanostructured layers are expected to be used especially in the case of known systemic or local (joint) inflammation. This layer can provide a bone tissue/implant (titanium alloy) bioactive interface improving the physiological healing process and eliminating the risk of bacterial orthopedic infections. The main aim of this study was to verify whether the local concentration of released vancomycin exceeded the minimum inhibitory concentration (MIC) for vancomycin-resistant Staphylococcus aureus (VRSA, >16 mg/l).

The layer is composed of collagen (type I, isolated form calf skin), hydroxyapatite nanoparticles and vancomycin hydrochloride (10 wt%). The stability of collagen was enhanced by EDC/NHS cross-linking. The in vitro release of vancomycin and crystalline degradation products from optimally cross-linked layers was investigated. An elution method and a high performance liquid chromatographic assay were employed to characterize the in vitro release rates of the vancomycin and its crystalline degradation antibacterial inactive products over a 21-day period.

During the whole experimental period, the level of released vancomycin was high above the MIC for VRSA. The maximum average concentration was obtained between day 4 and day 8 and it reached 265 mg/l. At the end of the experiment (day 21), an average concentration of 104 mg/l was detected.

Our study confirmed the prophylactic effects of studied vancomycin-loaded nanostructured layers