Controlled release of vancomycin hydrochloride from a composite structure of polymeric films and porous fibers on implants

- Antibiotic-loaded polymer films are easily deposited on implants by ESD technique.
- The polymer films have high loading capacity for VH.
- A porous fiber felt is covered onto the films that can slow release rate of VH.
- The density and size of the pores in the fiber felts can be adjusted by ethanol vapor.
- The release rate of VH can be discretionarily controlled by changing treatment time of ethanol vapor.

The antibiotic administration is critical for treating open fracture, especially for tainted bone caused by contamination and the implant. Localized delivery of antibiotics is preferred since it provides elevated antibiotic concentrations at the aiming infection site without systemic toxicity. In this study, a polymer-based composite film with high drug loading capacity and excellent controlled release behavior that can be potentially applied as antibiotics-carrying implants is proposed. First, vancomycin hydrochloride (VH) loaded polyvinyl alcohol-borax (PVA-B) microgels were deposited on the surface of Ti metal straight bone plate by an electrospray technique, porous polyvinyl butyral (PVB) fiber felts were then covered onto the surface of the VH@PVA-B films using electrospinning technique in order to prohibit the free diffusion of VH molecules. The density and size of the pores in the fiber felts can be readily adjusted by exposing the fiber felts to the saturated ethanol vapor, which further controlling the release behavior of the VH molecules from the VH@PVA-B/PVB systems. Importantly, the results showed that our VH@PVA-B/PVB systems with different release behaviors adjustable by the density and size of the pores are all effective to kill S. aureus, as the released VH concentration from the investigated systems are all well above the minimum effective concentration. This study provides a universal strategy to fabricate therapeutic drugs-loaded coatings on implants with the ability to control drug release behaviors.

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