ANTIBIOTIC RELEASE FROM FLUORIDE-TIO2 NANOSTRUCTURED ANODIC LAYERS ON TI6AL4V ALLOY

Introduction Prosthetic joint infections (PJI) occur infrequently, but due to its increased clinical use represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative staphylococci are the most common infecting agents associated with PJI. A possible therapeutic approach could be the local antibiotic by fluoride-TiO2 nanostructured anodic layers in order to prevent surface colonisation during the early moments after surgery. Here we describe the first results of this model using two common antibiotics. Methods Fluoride-TiO2 nanostructured anodic layers on Ti6Al4V alloy were produced as described previously by Arenas et al (2013). Discs shaped pieces of Ti6Al4V alloy were loaded with a solution of 150 mg antibiotic (vancomycin or gentamicin)/20 ml sterile distilled water. Samples were immersed in this solution during 24 hours at room temperature with agitation, and then were dried during 48 hours at 20°C. Antibiotic release was studied by introducing both discs in sterile PBS and samples were taken at different times. Samples were then frozen at −80°C until HPLC measurements and biological activity tests using Bacillus subtilis ATCC 6051 (vancomycin) and Escherichia coli ATCC 25922 (gentamicin) were performed. Results Release kinetic constant was not be obtained by HPLC-UV due to chemical degradation, therefore it was needed to prove biological activity. According to biological activity test, vancomycin and gentamicin estimated concentration mean and standard deviation were 2.9±0.61 and 2.71±0.64 mg/L over time respectively. Conclusions Fluoride-TiO2 nanostructured anodic layers on Ti6Al4V alloy could be considered as promising vector of antibiotics for the prevention of PJI during early moments after surgery.