Synonyms: 5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid,7-[[(3-chloro-5-isoxazolyl)acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-,monosodium salt, (6R,7R)- (9CI); 5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid,7-[[(3-chloro-5-isoxazolyl)acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-,monosodium salt, (6R-trans)-; BK 218