Dopa decarboxylase inhibitor compositions

Abstract

Disclosed herein are formulations containing carbidopa and optionally levodopa, arginine, and other components that have reduced levels of impurities and toxins, particularly degradation productions. Also disclosed herein are methods of treatment diseases or conditions relating to a loss of dopamine or dopaminergic neurons using such formulations, methods of making such formulations, and kits that include such formulations.

What is claimed is: 
     
         1 . A method for treating Parkinson's disease in a patient, the method comprising administering to the patient a pharmaceutically acceptable formulation in an amount effective to treat the Parkinson's disease in the patient, wherein the pharmaceutically acceptable formulation comprises:
 about 0.1% to about 10% by weight ascorbic acid or a pharmaceutically acceptable salt thereof;   about 0.01% to about 1% by weight of a component selected from the group consisting of:   NAC, L-cysteine, and pharmaceutically acceptable salts thereof;   about 2% to about 16% by weight levodopa or an ester thereof; and   about 0.6% to about 1.4% by weight carbidopa or an ester thereof, and   wherein the pharmaceutically acceptable formulation has less than about 10 μg/ml of hydrazine, as determined by a gas chromatography-mass spectrometry (GCMS) method.   
     
     
         2 . The method of  claim 1 , wherein the administering is substantially continuous. 
     
     
         3 . The method of  claim 1 , wherein the formulation comprises less than about 1 μg/ml of hydrazine, as determined by a GCMS method. 
     
     
         4 . The method of  claim 1 , wherein the formulation comprises about 0.1 μg/ml to about 2 μg/ml of hydrazine, as determined by a GCMS method. 
     
     
         5 . The method of  claim 1 , wherein the formulation further comprises about 10% to about 40% by weight of a component selected from the group consisting of: a natural basic amino acid, an amino sugar, and combinations thereof. 
     
     
         6 . The method of  claim 5 , wherein the natural basic amino acid is arginine. 
     
     
         7 . The method of  claim 5 , wherein the amino sugar is meglumine. 
     
     
         8 . The method of  claim 1 , wherein the formulation comprises about 11% to about 15% by weight levodopa. 
     
     
         9 . The method of  claim 1 , wherein the formulation comprises about 12% to about 14% by weight levodopa. 
     
     
         10 . The method of  claim 1 , wherein the formulation further comprises a surfactant. 
     
     
         11 . The method of  claim 10 , wherein the formulation comprises about 0.01% to about 5% polysorbate 80. 
     
     
         12 . The method of  claim 1 , wherein the formulation after 30 days at −20° C., has less than about 0.2% by weight 3,4-dihydroxyphenyl-2-methylpropionic acid, as determined by HPLC. 
     
     
         13 . The method of  claim 1 , wherein the formulation is a liquid formulation. 
     
     
         14 . The method of  claim 1 , wherein the pharmaceutically acceptable salt of ascorbic acid is sodium ascorbate. 
     
     
         15 . The method of  claim 1 , wherein the formulation has less than about 5% or less than about 1% by weight of a degradant, relative to the amount of carbidopa or an ester thereof, as determined by HPLC. 
     
     
         16 . The method of  claim 15 , wherein the degradant is a compound represented by the general formula (I): 
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof, wherein R 1 , R 2 , and R 3  are each independently selected from the group consisting of hydrogen, —R 7 (O)(OH) 2  and —R 5 —O—R 7 (O)(OH) 2 ; R 5  is a C 1 -C 4 -alkyl; R 6  is hydrogen or a C 1 -C 4 -alkyl; and R 7  is O, P, F or Cl. 
     
     
         17 . The method of  claim 16 , wherein the formulation has less than about 5% by weight of the compound represented by general formula (I), relative to the amount of carbidopa or an ester thereof, as determined by HPLC. 
     
     
         18 . The method of  claim 16 , wherein the formulation has less than about 1% by weight of the compound represented by general formula (I), relative to the amount of carbidopa or an ester thereof, as determined by HPLC. 
     
     
         19 . The method of  claim 16 , wherein the compound represented by general formula (I) is 3,4-dihydroxyphenyl-2-methylpropionic acid. 
     
     
         20 . A method for treating Parkinson's disease, the method comprising substantially continuously subcutaneously administering to a patient in need thereof a liquid composition comprising:
 about 0.1% to about 10% by weight ascorbic acid or a pharmaceutically acceptable salt thereof;   about 0.01% to about 1% by weight of a component selected from the group consisting of:   NAC, L-cysteine, and pharmaceutically acceptable salts thereof;   about 2% to about 16% by weight levodopa or an ester thereof; and   about 0.6% to about 1.4% by weight carbidopa or an ester thereof, and   wherein the method comprises administering less than 42 μg/day of hydrazine to the patient.