Crystalline hydrates of cephalosporin and process for preparation thereof

The present invention relates to a crystalline hydrate of 7-[(Z)-2-(2-aminothiazole-4-yl)-2-(2-carboxylprop-2-oxyimino) acetamido]-3-(5-methyl-1,4,6-triaminopyrimidinium-2-yl) thiomethyl-3-cephem-4-carboxylate and a composition comprising said compound as an active ingredient. Also provided herein is a process for preparation of the compound which comprises the steps of: dissolving the compound in an amorphous form or its salt in an acidic or basic solution; adjusting the pH of the solution to a range from 1.5 to 5.5 by adding a basic or acidic solution; precipitating the compound in a crystalline form in the solution; and recovering said crystalline hydrate of the compound.