title: Ultra-long-duration local anesthesia produced by injection of lecithin-coated tetracaine microcrystals.
abstract: This study was designed to determine if microencapsulated tetracaine would provide a longer duration of local anesthesia than nonmicroencapsulated (neat) tetracaine. Local anesthesia was determined by monitoring the response of the rat to tail clamping after the installation of a subcutaneous ring block. Ten percent microencapsulated tetracaine was found to provide local anesthesia of the tail for a 43-hour duration. Ten percent tetracaine solution was toxic. One percent tetracaine solution provided a tail block lasting 8 hours. Lecithin membranes without drug provided no block. This study demonstrates that lecithin-coated tetracaine microcrystals produce a local anesthetic effect that is ultra-long in duration, reversible, and not systemically toxic.
authors.affiliation: Department of Anesthesiology, Walter Reed Army Medical Center, Washington, DC 20307-5001.
authors.forename: B H
authors.initials: BH
authors.lastname: Boedeker
authors.forename: E W
authors.initials: EW
authors.lastname: Lojeski
authors.forename: M D
authors.initials: MD
authors.lastname: Kline
authors.forename: D H
authors.initials: DH
authors.lastname: Haynes
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002214:Capsules; D008297:Male; D010147:Pain Measurement / Q000187:drug effects; D010316:Particle Size; D010713:Phosphatidylcholines; D051381:Rats; D017207:Rats, Sprague-Dawley; D013748:Tetracaine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000779:Anesthetics, Local; D002214:Capsules; D010713:Phosphatidylcholines; D013748:Tetracaine