In an effort to localize the effects of anesthesia, researchers have turned to magnetic nanoparticles to target the delivery of ropivacaine in a proof-of-concept animal study.
Using iron oxide nanoparticles injected intravenously into rats, the team from the University of Pittsburgh attached magnets to the animals' ankles to draw the nanoparticles to that area and numb the nerves in that specific location. With the anesthetizing agent drawn to one paw in particular, the other paw was not affected, according to a report from the International Anesthesia Research Society, whose journal Anesthesia & Analgesia published the study.
The study suggests that a higher dose of ropivacaine can be used when targeted this way. In fact, the team used a high enough dose of the drug that it could have been fatal for the rats, but none of the animals showed any adverse effects. This was a 14-fold dose increase.
"We have established proof of principle that it is possible to produce ankle block in the rat by intravenous injection of magnetic nanoparticles associated with ropivacaine and magnet application at the ankle," lead author Venkat Mantha said in a statement.
The team plans to continue animal testing to prove the safety of the procedure before moving into human trials.