Lyophilized or precipitated cephalosporin zwitterion and salt composition

Abstract From the Canadian patent

Amorphous solid formed by lyophilization or cosolvent precipitation of an aqueous solution of 7-.alpha.-(2-aminothiazol-4-yl)-.alpha.-(Z)-methoximinoacetamido-3-(1-methyl-1pyrrolidinio)-methyl-3-cephem-4-carboxylate zwitterion and a salt or mixture of salts from a selected particular group is a broad spectrum antibiotic composition and has better temperature stability at least up to 45°C than the zwitterion. The salt is one wherein the cation is selected from the group consisting of sodium, lithium calcium, and, magnesium and the anion is selected from the group consisting of chloride, bromide, and iodide. The molar ratio of zwitterion to salt ranges from about 0.5:1 to about 2:1.