• Polymyxin B sulfate-loaded bone cement shows sustained release with peak release at 0-0.5 h and 90% of total release within 7 days.
• Smaller (5 mm) bone cement microspheres exhibit higher drug release rate and cumulative release compared to larger (7 mm) ones.
• The release kinetics follow the Ritger-Peppas model with Fickian diffusion as the dominant mechanism.
• Optimal timing for secondary debridement is 5-7 days post-implantation to balance efficacy and minimize resistance risk.