The Impact of Different Radiopacifying Agents on the Elution and Mechanical Properties of Vancomycin-loaded Bone Cements.

Antibiotic-loaded poly methyl methacrylate (PMMA) bone cements are used as one of the most effectual means to prevent orthopedic-implant associated infections. In the development of the orthopedic implants containing antibiotics, the drug elution behavior is of great importance. PMMA is radiolucent and mineral radiopacifying agents are commonly used to provide sufficient radiopacity. In this study, calcium tungstate, bismuth oxychloride, and barium sulfate as radio-opacifying agents are incorporated into Vancomycin (Vanco)-loaded PMMA bone cements. The effect of Vanco content and different type of radiopacifier on the handling properties, in vitro Vanco elution profiles, morphology, contact angle, mechanical, and antimicrobial properties of the prepared bone cements are evaluated. The results show that the Vanco elution profiles are influenced by the composition and wettability of the cement surface. It is observed that, after 21 days, the released vancomycin from the sample containing 7% Vanco with higher wettability increased approximately six fold compared to the sample with 1% Vanco. The sample containing bismuth oxychloride exhibited higher contact angle resulting in a reduced vancomycin release rate. Consequently, the drug elution and antibacterial activity of the cements depend on the drug content than the type of radiopacifying agents. Our findings introduce alternative radiopacifying agents for the cements and provide an insight into the elution behavior of Vanco in the cements.