FORFARANDE FOR RENING AV CEFALEXIN

1327048 Purification of cephalexin GLAXO LABORATORIES Ltd 19 April 1971 [11 March 1970] 11754/70 Heading C2A A process for the purification of cephalexin, i.e. 7# - (D - 2 - amino - 2 - phenylacetamido)- 3-methylceph-3-en-4 carboxylic acid, containing impurities, which comprises contacting an aqueous acid solution of said cephalexin with acetonitrile in quantities such that the volume of acetonitrile present is at least 70% of the volume of water, bringing the pH of the solution to from 3À5 to 4À5 by the addition of a base, e.g. ammonia or a triethylenine, so that a crystalline acetonitrile solvate of cephalexin forms, separating the solvate thereby obtained, suspending the solvate in water at a temperature of at least 58‹ C., allowing said crystalline solvate to dissolve therein, and recovering pure, substantially acetonitrile free, crystalline cephalexin from said solution. Reference has been directed by the Comptroller to Specification 1,174,335.