Abstract: The invention relates to a substantially anhydrous crystalline cefadroxil having a water content between about 0.8% and 3.9%.Such cefadroxil is obtained slurrying a cefadroxil solvate of dimethylacetamide, or of N-methyl-2-pyrrolidone or of monomethylformamide, with isopropyl alcohol with up to 4% of water and preferably in the presence of methanol in an amount lower than 60%, at a temperature of about +45.degree. C. to +55.degree. C. and then filtering the so obtained compound.
Abstract: The invention relates to a novel crystalline cefadroxyl hemihydrate having a K.F. between about 3.5 and 2.0%: such compound is more stable than other cefadroxyl molecules.The novel cefadroxyl is obtained preparing and isolating a novel cefadroxil solvate of dimethylacetamide, or of N-methyl-2-pyrrolidone or of monomethylformamide, slurrying and solvate with a mixture methanol/isporpyl alcohol 30:70 to 50:50 by volume at a temperature of about +45.degree. C. to +55.degree. C. and then filtering the so obtained compound.
Abstract: The invention relates to a novel crystalline cefadroxyl hemihydrate having a K.F. between about 3.5 and 2.0%: such compound is more stable than other cefadroxyl molecules.The novel cefadroxyl is obtained preparing and isolating a novel cefadroxil solvate of dimethylacetamide, or of N-methyl-2-pyrrolidone or of monomethylformamide, slurrying said solvate with a mixture methanol/isopropyl alcohol 30:70 to 50:50 by volume at a temperature of about +45.degree. C. to +55.degree. C. and then filtering the so obtained compound.
Abstract: The invention relates to a method for producing crystalline cefadroxil hemihydrate. According to the method a cefadroxil solvate is slurried with a mixture methanol:isopropyl alcohol 30:70 to 70:30 by volume containing from 5% to 12% of water, a temperature from +45.degree. C. to +55.degree. C. and then isolating the so obtained crystalline compound.
Abstract: 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% of water at a temperature between +45.degree. to +55.degree. 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.
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