Sustained release of vancomycin from novel biodegradable nanofiber-loaded vascular prosthetic grafts: in vitro and in vivo study

Abstract

This study describes novel biodegradable, drug-eluting nanofiber-loaded vascular prosthetic grafts that provide local and sustained delivery of vancomycin to surrounding tissues. Biodegradable nanofibers were prepared by first dissolving poly(D,L)-lactide-co-glycolide and vancomycin in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution was then electrospun into nanofibers onto the surface of vascular prostheses. The in vitro release rates of the pharmaceutical from the nanofiber-loaded prostheses was characterized using an elution method and a high-performance liquid chromatography assay. Experimental results indicated that the drug-eluting prosthetic grafts released high concentrations of vancomycin in vitro (well above the minimum inhibitory concentration) for more than 30 days. In addition, the in vivo release behavior of the drug-eluting grafts implanted in the subcutaneous pocket of rabbits was also documented. The drug-eluting grafts developed in this work have potential applications in assisting the treatment of vascular prosthesis infection and resisting reinfection when an infected graft is to be exchanged.

Keywords: drug-eluting prosthetic graft; release characteristics; vascular prosthesis infection.

Figure 1

The electrospinning setup shown schematically.

Figure 2

Photograph of the vascular prosthetic grafts (top, loaded with nanofibers; bottom, bare graft).

Figure 3

SEM photograph of electrospun drug-eluting nanofibers. Abbreviation: SEM, scanning electron microscope.

Figure 4

In vitro release of vancomycin from the drug-eluting grafts (n=3). Notes: (A) Daily release, and (B) accumulated release. Abbreviation: MIC₉₀, 90% minimum inhibitory concentration.

Figure 5

The implantation of drug-eluting grafts into the subcutaneous pockets of rabbits. Notes: (A) The drug-eluting graft was cut into 2 cm in length. (B) The implantation of drug-eluting grafts into the subcutaneous pockets of rabbits.

Figure 6

In vivo release behavior of the drug-eluting grafts.