Formulation for the treatment of pain

Abstract

Formulations and methods are provided for the treatment of pain, and neuropathic pain in particular. The formulations are eutectic mixtures of a capsaicinoid and a local anesthetic agent and/or an anti-pruritic agent.

1 . A substantially nonaqueous therapeutic formulation comprising a binary eutectic mixture of:
 (a) a capsaicinoid having the structure of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrogen, hydroxyl or methoxy, R 2  is hydroxyl or C 2 -C 6  alkoxycarbonyl, X is selected from 
       
         
           
           
               
               
           
         
       
       and R is selected from C 5 -C 11  alkyl, C 5 -C 11  alkenyl, C 11 -C 23  cis-alkenyl, C 11 -C 23  alkynyl, and C 11 -C 23  alkadienyl, provided that the capsaicinoid is other than capsaicin; and
 (b) a second active agent effective to decrease at least one side effect associated with capsaicin monotherapy, said second agent existing as a solid at 25° C. 
 
     
     
         2 . The formulation of  claim 1 , wherein the capsaicinoid is selected from resiniferatoxin, N-vanillyl-alkadienamides, N-vanillyl-alkanedienyls, N-vanillyl-monounsaturated alkenamides, N-vanillylsulfonamides, and hydroxyphenylacetamides. 
     
     
         3 . The formulation of  claim 2 , wherein the capsaicinoid is an N-vanillyl monounsaturated alkenamide. 
     
     
         4 . (canceled) 
     
     
         5 . The formulation of  claim 1 , wherein the second active agent is a local anesthetic agent. 
     
     
         6 . The formulation of  claim 5 , wherein the local anesthetic agent is selected from amylocaine, articaine, benzocaine, bupivacaine, butacaine, 2-chloroprocaine, cinchocaine, dexivacaine, diamocaine, dibucaine, etidocaine, ketocaine, lidocaine, mepivacaine, oxybuprocaine, parethoxycaine, prilocaine, procaine, propanocaine, proparacaine, propoxycaine, pyrrocaine, risocaine, rodocaine, ropivacaine, tetracaine, and combinations thereof. 
     
     
         7 . The formulation of  claim 6 , wherein the local anesthetic agent is lidocaine. 
     
     
         8 . The formulation of  claim 6 , wherein the local anesthetic agent is tetracaine. 
     
     
         9 . The formulation of  claim 5 , wherein the capsaicinoid represents about 10 wt. % to about 70 wt. % of the formulation. 
     
     
         10 . The formulation of  claim 9 , wherein the capsaicinoid represents about 40 wt. % to about 70 wt. % of the formulation. 
     
     
         11 . The formulation of  claim 5 , wherein the second active agent is an anti-pruritic agent. 
     
     
         12 . The formulation of  claim 11 , wherein the anti-pruritic agent is selected from menthol, camphor, phenol, and combinations thereof. 
     
     
         13 . The formulation of  claim 12 , wherein the capsaicinoid represents 10 wt. % to about 70 wt. % of the formulation. 
     
     
         14 . The formulation of  claim 13 , wherein the capsaicinoid represents about 40 wt. % to about 70 wt. % of the formulation. 
     
     
         15 - 24 . (canceled) 
     
     
         25 . The formulation of  claim 12 , wherein the capsaicinoid represents 10 wt. % to about 50 wt. % of the formulation. 
     
     
         26 . (canceled) 
     
     
         27 . The method of  claim 12 , wherein the eutectic mixture is administered by injection. 
     
     
         28 . A method for treating a patient suffering from pain, comprising administering to the patient a therapeutically effective amount of the formulation of  claim 1 . 
     
     
         29 . The method of  claim 28 , wherein the formulation is administered topically. 
     
     
         30 . The method of  claim 29 , wherein the pain is caused by inflammation of joints, tendons, nerves, or muscle. 
     
     
         31 - 33 . (canceled) 
     
     
         34 . The method of  claim 28 , wherein the pain is caused by cancer. 
     
     
         35 . The method of  claim 28 , wherein the pain is neuropathic pain. 
     
     
         36 - 39 . (canceled)