Chemical Name: (6R,7R)-3-[(acetyloxy)methyl]-8-oxo-7-[(1H-tetrazol-1-ylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid Sodium salt (as per EP); (6R,7R)-7-[2-(1H-Tetrazol-1-yl)acetamido]-3-(acetoxymethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid Sodium salt (as per USP)