Effect of magnetic nanoparticles containing ropivacaine on ankle nerve block in rats

Ropivacaine (RVC), a common pain management drug used for clinical anesthesia and postoperative analgesia, inhibits peripheral nociceptive pain stimulation. However, the potential neurological damage resulting from RVC use must be considered. Developing a strategy to enhance the local anesthetic effect of RVC while reducing its potential acute toxicity to the central nervous system is urgently needed. In this study, a novel RVC nanocomposite drug, magnetic iron oxide/polyethylene glycol-carboxymethyl chitosan/ropivacaine nanoparticle (mCMCS-PEG/RVC NPs), was synthesized with magnetic iron oxide. The inherent shell–core structure of mCMCS-PEG retained core magnetic properties, improved the stability and biocompatibility of magnetic nanoparticles, and avoided excessive degradation. Thus, mCMCS-PEG/RVC NPs are expected to provide a new pain management strategy for perioperative patients.