Boston Children's Hospital researchers develop long-lasting local anesthesia

Researchers at Boston Children's Hospital have developed a method to extend the effectiveness of local anesthesia from hours to weeks. By redesigning liposomes—microscopic fatty carriers—to release medication more slowly, the team achieved sustained effects in mice for two to three weeks.

Traditional commercial formulations typically provide relief for only four to eight hours, while most local anesthetics last between eight to twelve hours or up to one day. The breakthrough involves utilizing more fluid lipids to house hydrophilic (water-soluble) drugs, which the researchers discovered leak much more slowly than previously expected.

To test the potential for nerve blocks, the team used tetrodotoxin, a potent anesthetic found in pufferfish and blue-ringed octopuses. In mouse trials, the injection of this formulation near a nerve did not result in toxicity in the injection site or elsewhere in the body.