Poly (ε-caprolactone) coating delays vancomycin delivery from porous chitosan/β-tricalcium phosphate composites

The orthopedic infection, such as osteomyelitis, especially those caused by Methicillin-resistant Staphylococcus aureus (MRSA), remains a major complication of open fractures. Local vancomycin delivery is considered to provide better methods when avascular zones prevent the delivery of drugs from conventional routes of administration. Chitosan (CS) delivery system has been developed with the disadvantages, such as mechanically weakness, lacking osteoconductivity, and the initial burst of antibiotics into the environment. The aim of this study was to confirm that the prepared CS/β-tricalcium phosphate (β-TCP) composites coated with poly (ε-caprolactone) (PCL), similar to natural bone in components, had a three-dimensional porous structure and could be used as drug carriers to deliver vancomycin in a sustained and controlled manner effectively for 6 weeks at levels to inhibit MRSA proliferation. We prepared porous CS/β-TCP composites by incorporating β-TCP into the system, and coated the composites with PCL of three different concentrations. The morphological structure of composites, including pore size and porosity, was examined. The result showed that CS/β-TCP coated with 2.5w/v% PCL solution had the best coating effect and it retarded the release of vancomycin in a near zero-order mechanism from 0 to 14 days. The drug delivery was significantly delayed after coated with 2.5w/v% PCL. The quantitative release of vancomycin was extended to 42 days. Therefore PCL coating could be used to retard the release of vancomycin from CS/β-TCP composites in a sustained and controlled manner. Porous CS/β-TCP coated with PCL might be one of the candidate vancomycin carriers for treating MRSA-related osteomyelitis.