Dextrochlorpheniramine tannate

Abstract

The invention pertains to a novel composition comprising dextrochlorpheniramine tannate and to a method for preparing such tannate by reacting dextrochlorpheniramine free base at a temperature of about 60 to about 150° C. with tannic acid preferably neat or as an aqueous slurry containing about 5 to about 30 wt. % water. The dextrochlorpheniramine tannate has extended release properties and is useful in pharmaceutical compositions as an antihistamine for human beings.

What is claimed is:  
     
         1 . A composition comprising dextrochlorpheniramine tannate.  
     
     
         2 . The composition of  claim 1  having a purity level of at least about 95%.  
     
     
         3 . The composition of  claim 1  having a purity level of at least 97%.  
     
     
         4 . A therapeutic antihistaminic composition comprising a pharmaceutically effective amount of an active ingredient comprising dextrochlorpheniramine tannate.  
     
     
         5 . A therapeutic composition as claimed in  claim 4  in tablet form.  
     
     
         6 . A therapeutic composition as claimed in  claim 4  in suspension form.  
     
     
         7 . A therapeutic composition as claimed in  claim 4  further comprising one or more expectorant, antihistaminic and/or antitussive compositions.  
     
     
         8 . The composition of  claim 5  wherein the expectorant, antihistaminic and/or antihistamine compositions are selected from the group consisting of dextromethorphan, guaifenesin, brompheniramine, dextrobrompheniramine, pyrilamine, phenylephrine, ephedrine, pseudoephedrine, carbetapentane and carbinoxamine.  
     
     
         9 . A method for suppressing the production of histamines in a human being that comprises orally administering to such human being a therapeutic amount of a composition comprising an active ingredient comprising dextrochlorpheniramine tannate.  
     
     
         10 . A method as claimed in  claim 9  wherein said composition is in tablet form.  
     
     
         11 . A method as claimed in  claim 9  wherein said composition is in suspension form.  
     
     
         12 . A method for preparing dextrochlorpheniramine tannate which comprises reacting dextrochlorpheniramine free base with tannic acid at a temperature of about 60 to about 150° C. and thereafter recovering the resultant dextrochlorpheniramine tannate.  
     
     
         13 . The method of  claim 12  wherein the reaction is carried out at a temperature of 70 to 130° C.  
     
     
         14 . The method of  claim 12  wherein the dextrochlorpheniramine free base is employed in an amount of about 4 to about 8 moles of the free base per mole of tannic acid.  
     
     
         15 . The method of  claim 14  wherein the dextrochlorpheniramine free base is employed in an amount of 5 to 6 moles of the free base per mole of tannic acid.  
     
     
         16 . The method of  claim 12  wherein the resultant dextrochlorpheniramine tannate is dried under vacuum at a temperature of about 65 to about 75° C. for a period of 1 to 10 hours or more.  
     
     
         17 . The method of  claim 12  wherein the resultant dextrochlorpheniramine tannate is dried by sparging with nitrogen for a period of 1 to 10 hours or more.  
     
     
         18 . The method of  claim 12  wherein the resultant dextrochlorpheniramine tannate is milled to provide a free-flowing powder.  
     
     
         19 . The method of  claim 18  wherein the powder has a particle size in the range of about 50 to about 200 mesh.