Articles | Volume 3, issue 4
J. Bone Joint Infect., 3, 212–221, 2018
J. Bone Joint Infect., 3, 212–221, 2018

Original full-length article 04 Oct 2018

Original full-length article | 04 Oct 2018

In vitro study of new combinations for local antibiotic therapy with calcium sulphate - Near constant release of ceftriaxone offers new treatment options

Peter Wahl1,2, Karolin Rönn1,3, Marc Bohner4, Laurent A Decosterd5, Christoph Meier2, Michel Schläppi2, Sandrine Festa1, and Emanuel Gautier1 Peter Wahl et al.
  • 1Department of Orthopaedic Surgery, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland;
  • 2Division of Orthopaedics and Traumatology, Cantonal Hospital Winterthur, Winterthur, Switzerland;
  • 3Schulthess Clinic, Zürich, Switzerland;
  • 4RMS Foundation, Bettlach, Switzerland;
  • 5Division of Clinical Pharmacology, University Hospital Centre CHUV, Lausanne, Switzerland.

Keywords: Calcium sulphate, CaSO4, in vitro elution, antibiotics, ceftriaxone

Abstract. Introduction: Local application of antibiotics provides high concentrations at the site of interest, with minimal systemic toxicity. Carrier materials might help manage dead space. Calcium sulphate (CaSO4) has a dissolution time that only slightly exceeds the usually recommended duration of systemic antibiotic treatments. This in vitro study evaluates compatibility, release kinetics and antibacterial activity of new combinations of antibiotics with CaSO4 as carrier material.

Methods: CaSO4 pellets added with 8% w/w antibiotic powder were exposed once in phosphate-buffered saline (PBS) solution and once in bovine plasma, in an elution experiment run over 6 weeks at 37 °C. Antibiotic elution was examined at various time points. Concentration was measured by liquid chromatography with tandem mass spectrometry. Antimicrobial activity was checked with an agar diffusion test.

Results: Piperacillin-tazobactam, ceftazidime, cefepime, and meropenem showed fast reduction of concentration and activity. Flucloxacillin and cefuroxime remained present in relevant concentrations for 4 weeks. Ciprofloxacin, levofloxacin and clindamycin lasted for 6 weeks, but also at cell toxic concentrations. Ceftriaxone showed a near-constant release with only a small reduction of concentration from 130 to 75 mg/l. Elution profiles from PBS and plasma were comparable.

Conclusion: CaSO4 provides new possibilities in the local treatment of bone and joint infections. Ceftriaxone appears to be of particular interest in combination with CaSO4. Release persists at clinically promising concentrations, and appears to have a depot-like slow release from CaSO4, with only a small reduction in activity and concentration over 6 weeks. To the best of our knowledge, such a particular persistent release never was described before, for any antibiotic in combination with a carrier material for local application.