Get Best Price for77768-57-15-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 3-[[[1-(carboxymethyl)-1H-tetrazol-5-yl]thio]methyl]-7-[[[[(6,7-dihydroxy-4-oxo-4H-1-benzopyran-3-yl)carbonyl]amino](4-hydroxyphenyl)acetyl]amino]-8-oxo-, monosodium salt