Process for the Purification of Meloxicam

Abstract

A process for purifying meloxicam form I from a crude meloxicam, which comprises: i. contacting the crude meloxicam with an amine in a non-aqueous solvent to form a meloxicam salt; ii. isolating the meloxicam salt; iii. dissolving the meloxicam salt in an aqueous solvent to form a salt solution; and iv. adding an acid to the salt solution to precipitate free meloxicam.

1 . A process for purifying meloxicam form I from a crude meloxicam, which comprises:
 i. contacting the crude meloxicam with an amine in a non-aqueous solvent to form a meloxicam salt;   ii. isolating the meloxicam salt;   iii. dissolving the meloxicam salt in an aqueous solvent to form a salt solution; and   iv. adding an acid to the salt solution to precipitate free meloxicam.   
     
     
         2 . The process of  claim 1  wherein the crude meloxicam is in the form of a solid. 
     
     
         3 . The process of  claim 1  wherein the crude meloxicam is contacted with a primary amine. 
     
     
         4 . The process of  claim 1  wherein the crude meloxicam is contacted with N-methyl glucamine or triethylamine. 
     
     
         5 . The process of  claim 1  wherein the non-aqueous solvent comprises an alcohol. 
     
     
         6 . The process according to  claim 5  wherein the alcohol is ethanol. 
     
     
         7 . The process of  claim 1  the meloxicam salt is isolated by precipitation of the salt by addition of an antisolvent followed by filtration. 
     
     
         8 . The process according to  claim 7  wherein the antisolvent is an acid alcohol ester. 
     
     
         9 . The process according to  claim 8  wherein the acid alcohol ester is an alkyl acetate. 
     
     
         10 . The process of  claim 1  wherein the aqueous solvent is water. 
     
     
         11 . The process of  claim 1  wherein the acid is acetic, hydrochloric, sulphuric or phosphoric acid. 
     
     
         12 . The process according to  claim 11  wherein the acid is acetic acid. 
     
     
         13 . The process of  claim 1  wherein carbon is also added to the salt solution. 
     
     
         14 . The process of  claim 1  wherein the precipitated meloxicam is subsequently filtered, washed and dried.