1-[[7-[[(2-Amino-4-thiazolyl)(methoxyimino)acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]-1-methyl-Pyrrolidinium

1-[[7-[[(2-Amino-4-thiazolyl)(methoxyimino)acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]-1-methyl-Pyrrolidinium is an impurity of Ceftriizine (C237575), a new orally administered cephalosporin with excellent activity against gram-positive cocci, inhibiting all except enterococci at minimal inhibitory concentrations below 1 μg/ml.