Volatile anesthetic compositions comprising extractive solvents for regional anesthesia and/or pain relief

Abstract

The present invention provides methods for reducing pain in a subject in need of such pain reduction by delivering, e.g., intrathecally or epidurally, a volatile anesthetic dissolved in a solution comprising an extractive solvent, e.g., DMSO or NMP, in an amount effective to reduce pain. Chronic or acute pain may be treated, or the anesthetic may be delivered as a regional anesthesia to a subject to anesthetize a portion the subject prior to a surgery. In certain embodiments, isoflurane, halothane, enflurane, sevoflurane, desflurane, methoxyflurane, or mixtures thereof may be used. Dosing regimens including a one-time administration, continuous and/or periodic administration are contemplated.

1 - 66 . (canceled) 
     
     
         67 . A method for reducing pain in a subject in need of such pain reduction, the method comprising administering to the subject a pharmacologically acceptable solution having a volatile anesthetic dissolved therein in an amount effective to reduce pain,
 wherein the solution further comprises an extractive solvent in an amount effective to reduce volatility of the volatile anesthetic;   wherein the solution is delivered to the subject by a route selected from the group consisting of mucosal, buccal, rectal, vaginal, and subcutaneous; and   wherein the volatile anesthetic is selected from the group consisting of isoflurane, halothane, enflurane, sevoflurane, desflurane, methoxyflurane, and mixtures thereof.   
     
     
         68 . The method of  claim 67 , wherein the extractive solvent is dimethyl sulfoxide (DMSO), dimethylformamide, dimethylacetamide, N-Methyl-2-pyrrolidone (NMP), dimethylisosorbide, ethanol, propanol, or isopropanol. 
     
     
         69 . The method of  claim 67 , wherein the volatile anesthetic is the only analgesic agent present in the solution in an amount sufficient to reduce pain in the subject. 
     
     
         70 . The method of  claim 67 , wherein the extractive solvent comprises from about 10% to about 75% of the solution. 
     
     
         71 . The method of  claim 67 , wherein the extractive solvent comprises from about 10% to about 25% of the solution. 
     
     
         72 . The method of  claim 67 , wherein the extractive solvent comprises from about 25% to about 75% of the solution. 
     
     
         73 . The method of  claim 67 , wherein the pain is chronic pain. 
     
     
         74 . The method of  claim 67 , wherein the pain is acute pain. 
     
     
         75 . The method of  claim 67 , wherein the solution is delivered to anesthetize a portion of the subject prior to a surgery, during a surgery, or after a surgery. 
     
     
         76 . The method of  claim 67 , wherein the volatile anesthetic is isoflurane. 
     
     
         77 . The method of  claim 67 , wherein the volatile anesthetic is sevoflurane. 
     
     
         78 . The method of  claim 67 , wherein the volatile anesthetic is methoxyflurane. 
     
     
         79 . The method of  claim 67 , wherein the solution comprises from about 10% to about 99% v/v anesthetic in solution. 
     
     
         80 . The method of  claim 79 , wherein the solution comprises from about 10% to about 75% v/v anesthetic in solution. 
     
     
         81 . The method of  claim 79 , wherein the solution comprises from about 75% to about 99% v/v anesthetic in solution. 
     
     
         82 . The method of  claim 67 , wherein the delivery of the solution is periodic. 
     
     
         83 . The method of  claim 67 , wherein the delivery of the solution is a one-time event. 
     
     
         84 . The method of  claim 67 , wherein the delivery of the solution is periodically administered to the subject on separate occasions. 
     
     
         85 . The method of  claim 67 , wherein the reduction comprises elimination of pain perception of a portion of the body of the subject. 
     
     
         86 . The method of  claim 67 , wherein the solution comprising the volatile anesthetic is sterile. 
     
     
         87 . The method of  claim 67 , wherein the subject is a human. 
     
     
         88 . The method of  claim 67 , wherein the subject is a mouse or a rat. 
     
     
         89 . The method of  claim 67 , wherein the extractive solvent is DMSO or ethanol, and wherein the volatile anesthetic is isoflurane. 
     
     
         90 . The method of  claim 89 , wherein the extractive solvent comprises from about 10% to about 50% of the solution. 
     
     
         91 . The method of  claim 67 , wherein the extractive solvent is DMSO or ethanol, and wherein the volatile anesthetic is sevoflurane. 
     
     
         92 . The method of  claim 91 , wherein the extractive solvent comprises from about 10% to about 50% of the solution. 
     
     
         93 . The method of  claim 67 , wherein the pain reduction is achieved without substantially interfering with motor function or without inhibition of motor function. 
     
     
         94 . The method of  claim 67 , wherein the solution is administered more than once and timed to achieve pain reduction without substantially interfering with motor function or without inhibition of motor function.