Novel doped calcium phosphate-PMMA bone cement composites as levofloxacin delivery systems

• Novel BC composites with improved mechanical integrity.
• Sustained in vitro release of the antibiotic (levofloxacin) from the BC composites over an 8-week period.
• Levofloxacin retained the antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis over an 8-week in vitro release period.
• Biocompatible BC composites.

Antibiotic-loaded acrylic bone cements (ALABCs) are well-established and cost-effective materials to control the occurrence of bone and joint infections. However, the inexistence of alternative antibiotics other than those already commercially available and the poor ability to bind to bone tissue hampering its biological function are still major drawbacks of ALABCs clinical application. The concept of this research work is to develop a novel bone cement (BC) drug delivery system composed by Mg- and Sr-doped calcium phosphate (CaP) particles as drug carriers loaded into a lactose-modified acrylic BC, which, to the best of our knowledge, has never been reported. CaP particles are known to promote bone ingrowth and current research is focused on using these carriers as antibiotic delivery systems for the treatment of bone infections, like osteomyelitis. Levofloxacin is a fluoroquinolone with anti-staphylococcal activity and adequate penetration into osteoarticular tissues and increasingly being recommended to manage bone-related infections. Also, the lactose-modified BC matrix, with a more porous structure, has already proved to enhance antibiotic release from the BC inner matrix. This novel BC composite biomaterial has shown improved mechanical integrity, biocompatibility maintenance, and sustained release of levofloxacin, with concentrations over the minimum inhibitory concentration values after a 48 h while maintaining antibacterial activity over an 8-week period against Staphyloccocus aureus and Staphyloccocus epidermidis, common pathogens associated with bone infections.

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