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

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 1148.00 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.