Method for preparing crystalline cefadroxil monohydrate

摘要

The invention relates to a method for preparing crystalline cefadroxil monohydrate. According to such a method a cefadroxil solvate is slurried with isopropyl alcohol containing less 6% to 18% W/W of water at a temperature between + 45 and +55 DEG C: the crystalline cefadroxil monohydrate is isolated by filtration. Some of the cefadroxil solvates which can be used are novel: they are prepared by adding dimethylacetamide, N-methyl-2-pyrrolidone or monomethylformamide to an aqueous solution of cefadroxil at a pH between 5.5 and 6.