Scientists develop local anesthetic lasting weeks instead of hours

Researchers at Boston Children's Hospital redesigned liposomes to release a numbing drug gradually. In rats, anesthesia lasted two to three weeks versus four to eight hours for a commercial formulation. The carriers were loaded with tetrodotoxin, with no toxicity detected.

• In rats the effect lasted 2–3 weeks versus 4–8 hours for the commercial version
• The liposomes were loaded with tetrodotoxin, a pufferfish neurotoxin
• No toxicity was found at the injection site or elsewhere in the body
• The study was published in Nature Biomedical Engineering