A Comparative Study of Extended Gentamicin and Tobramycin Release and Antibacterial Efficacy from Palacos and Simplex Acrylic Cements

Antibiotic-loaded bone cements (ALBCs) are used to prevent and treat periprosthetic joint infections (PJI). This study compares the in vitro release and antibacterial effectiveness of gentamicin from Palacos® R+G and tobramycin from Simplex® T. Standardized cylindrical specimens of Palacos® R+G and Simplex® T were incubated in phosphate-buffered saline. Antibiotic release was quantified using high-performance liquid chromatography (HPLC) over 14 and 42 days. Antibacterial efficacy was assessed using inhibition zone tests (IZT) against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli over 42 days. Palacos® R+G exhibited a significantly higher and more sustained antibiotic release of gentamicin compared to tobramycin from Simplex® T. The cumulative release of gentamicin from Palacos® R+G was 1.148 µg/cm2, while Simplex® T released 198.87 µg/cm2 tobramycin over 14 days. Inhibition zone tests showed that Palacos® R+G maintained antibacterial activity for 42 days, while Simplex® T’s activity diminished after 14 days. Statistical analysis confirmed significant differences in antibacterial efficacy between the two cements. Palacos® R+G demonstrated superior gentamicin release and sustained antibacterial activity compared to tobramycin from Simplex® T. These findings suggest that Palacos® R+G may offer better clinical outcomes in preventing and treating PJIs.