Comparative Characteristics of Polymethyl Methacrylate Bone Cement and Polyurethane Polymer Carriers for Local Delivery of Polymyxin

Introduction. Bone implant-associated infections, particularly those caused by multidrug-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa, represent a serious clinical problem. Local delivery of antibiotics such as polymyxin is a promising strategy for overcoming resistance and combating biofilms. The aim of this study was to investigate the elution rate of polymyxin from two different polymer matrices (polymethyl methacrylate and a polyurethane carrier) against P. aeruginosa and K. pneumoniae strains. Materials and Methods. The elution rate and antibacterial activity of polymyxin incorporated into two polymeric materials were studied: one based on polymethyl methacrylate (PMMA) and one based on polyurethane polymers (PU). Polymyxin was added to the starting materials in two ratios: polymer:antibiotic 10g:0.25g; Polymer:antibiotic 10g:0.5g. Results. The volume of polymyxin released when the materials were saturated with a polymer:polymyxin ratio of 10g:0.25g was higher for the PU-based material (38.8%). When the materials were saturated with polymyxin at a polymer:polymyxin ratio of 10g:0.5g, the best yield was achieved for the PMMA-based material (75.6%). Both materials provided statistically significant antibacterial activity. PMMA demonstrated a more potent initial effect, while PU had a prolonged effect. In all cases, a dose-dependent antibacterial effect was observed. Discussion. Differences in release kinetics are related to the polymer structure: dense PMMA ensures rapid surface release, while porous polyurethane provides more prolonged diffusion. This determines potential clinical scenarios for their use – for rapid sanitation or long-term prophylaxis, respectively. Conclusion. Polymethyl methacrylate and polyurethane materials are effective systems for the local delivery of polymyxin, providing different release profiles, allowing material selection based on clinical needs.