The aim of this study was to develop a new
wound dressing with controlled release of
antibiotics only in the presence of
infection. In the first experiment using an infected dorsal pouch of rats, exudate containing
proteinases from pouches contaminated with Staphylococcus aureus or Pseudomonas aeruginosa showed significantly higher hydrolytic activity toward
Boc-Val-Pro-Arg-MCA than that from noninfected
wounds. The authors then developed a new type of
wound dressing (AGX), a drug delivery system in which
gentamicin is bound to polyvinylalcohol
hydrogel through an enzymatically degradable
peptide linker containing a -(
D)-Phe-Pro-Arg-sequence. To investigate in vitro effectiveness, AGX was incubated with exudate from S. aureus infected or P. aeruginosa infected
wounds.
Gentamicin was selectively released from AGX in the presence of the exudate from S. aureus infected or P. aeruginosa infected
wounds, but was not released in the presence of exudate from noninfected
wounds. Next, AGX or the polyvinylalcohol
hydrogel that served as control was incubated with S. aureus in the presence of human plasma. After 24 hours, S. aureus concentration was markedly lower in the case with AGX than in that with polyvinylalcohol
hydrogel. These results indicate that
proteinases from
wounds infected with S. aureus or P. aeruginosa cleaved the linker and
gentamicin was released.