Process for the crystallisation of cefadroxil monohydrate

Abstract

Cefodroxil monohydrate is formed by a processing which includes a) bringing an aqueous solution of cefadroxil monohydrate to a pH of between 7 to 9 with a suitable titrant; b) lowering the pH to a value of between 5 and 6.5 to obtain a suspension of cefadroxil monohydrate in crystal form; and c) isolating the cefadroxil monohydrate in crystal form from the suspension obtained in step b). The cefadroxil monohydrate thereby obtained exhibits a CIE b value of below 6, and advantageously a CIE b value of below 12 when stored at a temperature of 25° C. for at least 1 month.

1 . Cefadroxil monohydrate in crystal form obtained by a process comprising:
 a) bringing an aqueous solution of cefadroxil monohydrate to a pH of between 7 to 9 with a suitable titrant;   b) lowering the pH to a value of between 5 and 6.5 to obtain a suspension of cefadroxil monohydrate in crystal form; and   c) isolating the cefadroxil monohydrate in crystal form from the suspension obtained in step b).   
     
     
         2 . Cefadroxil monohydrate according to  claim 1 , wherein step a) and step b) are carried out at a temperature of between 5 and 25° C. 
     
     
         3 . Cefadroxil monohydrate according to  claim 1 , wherein lowering the pH in step b) is carried out within a period of time of between 20 to 60 min. 
     
     
         4 . Cefadroxil monohydrate according to  claim 1 , wherein the suspension of the cefadroxil monohydrate in crystal form obtained in step b) is stirred for 10 to 120 min. 
     
     
         5 . Cefadroxil monohydrate according to  claim 1 , wherein the cefadroxil in crystal form is isolated from the suspension obtained in step b). 
     
     
         6 . Cefadroxil monohydrate in crystal form with a CIE b value of below 6. 
     
     
         7 . Cefadroxil monohydrate in crystal form with a CIE b value of below 12 when stored at a temperature of 25t for at least 1 month. 
     
     
         8 . A pharmaceutical composition comprising cefadroxil monohydrate as defined in  claim 6 , and a pharmaceutically acceptable carrier.