Self-expanding PMMA composite bone cement with sustained release of gentamicin sulfate and alendronate using water absorption pathways

[Display omitted] •GS and ALN were sustainably released using the water absorption pathways.•SDBCs provided favorable expansion and mechanical properties.•SDBCs had excellent in vitro cellular activity and in vivo biocompatibility. Although drug-loaded polymethyl methacrylate (PMMA) bone cement had been widely used in the vertebroplasty and arthroplasty, the mismatch between the drug release cycle and clinical demand, as well as low drug release rate and single therapeutic effect restricted the use of PMMA bone cement as the drug carrier in clinical applications. In this study, poly(methyl methacrylate-acrylic acid)-alendronate [P(MMA-AA)-ALN] drug-loaded nanoparticles with anti-osteoporosis function were synthesized and introduced into the gentamicin sulfate (GS) loaded PMMA bone cement. The rapidly expandable bone cement with water absorption pathways was constructed by adjusting the particle size of P(MMA-AA)-ALN nanoparticles. More importantly, the sustained release of GS and ALN were creatively achieved by their migration through the water absorption pathways composed of P(MMA-AA)-ALN nanoparticles. The results showed that the cumulative release ratios of GS and ALN in the composites were up to 74.67 ± 1.02 % and 75.23 ± 1.96 %. Meanwhile, the release cycles of GS and ALN were extended to 4 weeks and 15 weeks, effectively preventing infection, and matching the normal bone healing cycle. In addition, the swelling and dual drug release bone cement (SDBC) displayed superior antibacterial activity and biocompatibility.