In vitro elution of tobramycin from bioabsorbable polycaprolactone beads.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Infectious Disease Research

Background:

• Antibiotic-impregnated beads are used to treat bone infections.
• Polycaprolactone (PCL) and polymethylmethacrylate (PMMA) are common biomaterials for bead fabrication.
• Optimizing antibiotic elution is crucial for effective treatment and minimizing resistance.

Purpose of the Study:

• To compare the in vitro elution characteristics of tobramycin-loaded PCL and PMMA beads.
• To evaluate the impact of incubation conditions (temperature, medium) on elution profiles.
• To assess the antibacterial efficacy of eluted tobramycin.

Main Methods:

• Tobramycin-impregnated 6mm PCL and PMMA beads (6% tobramycin) were prepared.
• Beads were incubated in phosphate-buffered saline or newborn calf serum at room temperature or 37°C for eight weeks.
• Tobramycin levels were quantified using fluorescent assay, and antibacterial activity was assessed via agar diffusion against Staphylococcus aureus and Pseudomonas aeruginosa.

Main Results:

• PCL beads exhibited significantly higher tobramycin elution rates than PMMA beads over eight weeks, especially at 37°C.
• At eight weeks, PCL eluted approximately four times more tobramycin than PMMA at room temperature and eight times more at 37°C.
• All tested beads maintained bacteriostatic activity against S. aureus and P. aeruginosa up to eight weeks.

Conclusions:

• PCL demonstrates superior in vitro antibiotic elution properties compared to PMMA.
• PCL holds potential as a more effective antibiotic delivery vehicle for treating bone infections.
• The bioabsorbable nature of PCL may eliminate the need for bead removal surgery.