A Ropivacaine-Eluting Poly(Lactide-Co-Caprolactone) Wound Dressing Provided Enhanced Analgesia in Partial-Thickness Porcine Injuries

Abstract

Background: Partial-thickness skin wounds are some of the most painful injuries because of large areas of exposed nerve endings. These injuries often require systemic opioid treatment to manage pain adequately. However, the Centers for Disease Control and Prevention reported nearly 17,000 prescription opioid-related deaths in the United States in 2021 alone, highlighting the ongoing need for nonopioid treatment strategies. The authors developed a novel single-application ropivacaine-eluting primary wound dressing that could provide sustained ropivacaine delivery to partial-thickness wounds and assessed its in vivo feasibility for prolonged nonopioid analgesia.

Methods: Sustained release of ropivacaine from a poly(lactide-co-caprolactone) matrix was first optimized in vitro using dissolution testing and a Box Behnken design of experiments. The optimized dressing was then tested against a clinical control silicone dressing in a porcine partial-thickness wound study to assess analgesic effect, pharmacokinetics, and wound healing.

Results: The ropivacaine-eluting dressing showed a moderate analgesic effect in vivo, where normalized single pinprick scores significantly improved pain over the testing period (4 to 168 hours) (control versus treatment: 232 ± 25% versus 145 ± 16%; P < 0.0003). Ropivacaine blood plasma levels peaked at 8 hours after treatment, with a maximum concentration of 246 ± 74 ng/mL. No significant differences in wound healing were found when compared with control.

Conclusion: The ropivacaine-loaded poly(lactide-co-caprolactone)-based wound dressing provided sustained delivery of ropivacaine to partial-thickness skin wounds and enhanced analgesic effect compared with a clinical standard control dressing.

Clinical relevance statement: This article describes the development and porcine testing of an analgesic wound dressing for management of acute pain in partial-thickness dermal wounds.