Concepts for increasing gentamicin release from handmade bone cement beads

Abstract

Background and purpose Commercial gentamicin-loaded bone cement beads (Septopal) constitute an effective delivery system for local antibiotic therapy. These beads are not available in all parts of the world, and are too expensive for frequent use in others. Thus, orthopedic surgeons worldwide make antibiotic-loaded beads themselves. However, these beads are usually not as effective as the commercial beads because of inadequate release kinetics. Our purpose was to develop a simple, cheap, and effective formulation to prepare gentamicin-loaded beads with release properties and antibacterial efficacy similar to the commercially ones.Methods Acrylic beads were prepared with variable monomer content: 100% (500 μL/g polymer), 75%, and 50% to increase gentamicin release through creation of a less dense polymer matrix. Using the optimal monomer content, different gel-forming polymeric fillers were added to enhance the permeation of fluids into the beads. Polyvinylpyrrolidone (PVP) 17 was selected as a suitable filler; its concentration was varied and the antibiotic release and antibacterial efficacy of these beads were compared with the corresponding properties of the commercial ones.Results Gentamicin release rate and the extent of release from beads prepared with 50% monomer increased when the PVP17 content was increased. Beads with 15 w/w% PVP17 released 87% of their antibiotic content. This is substantially more than the gentamicin release from Septopal beads (59%). Acrylic beads with 15 w/w% PVP17 reduced bacterial growth by up to 93%, which is similar to the antibacterial properties of the commercial ones.Interpretation A simple, cheap, and effective formulation and preparation process has been described for hand-made gentamicin-releasing acrylic beads, with better release kinetics and with antibacterial efficacy similar to that of the commercial ones.

Aminoglycoside-resistant staphylococci in Greece: prevalence and resistance mechanisms

“…For local prophylaxis, application of gentamicin in the bone cement as well as coating of metallic implants with tobramycin or gentamicin appear to be effective, resulting in improved long-term implant survival [8]. For the treatment of skeletal infections, gentamicin-loaded bone cement beads, tobramycin impregnated beads and bone graft substitutes offer high concentrations of antibiotics at the site of infection [9]. However, local usage of aminoglycosides could rapidly induce antibiotic resistance among staphylococci with subsequent reduced effect on prophylaxis [10].…”

Biomaterials approaches to treating implant-associated osteomyelitis

“…The commercially prepared Septopal beads are an exception, as they are able to release 35% of the loaded gentamicin due to higher porosity [87]. Based on this concept, many fillers and mixing techniques have been studied to increase the PMMA porosity and release efficiency from manually prepared beads and spacers [6, 82, 83, 107], but there are no widely accepted standards for intraoperative preparation of antibiotic-laden PMMA.…”

Amphotericin B Delivery From Bone Cement Increases With Porosity but Strength Decreases

“…Previous studies have established that adding a soluble poragen [11,13,14] or an insoluble filler like hydroxypropylmethylcellulose [17] to PMMA will improve the release of hydrophilic antibacterials like aminoglycosides or vancomycin. A high-dose poragen load (greater than 10 vol%) is considered necessary to give PMMA extensive interconnecting pores equivalent to high-dose antibacterial loaded bone cement [12].…”