Cloxacillin (base and/or unspecified salts)

3-dimethyl-7-oxo-thyl-4-isoxazolecarboxamido)-

[3-(o-chlorophenyl)-5-methyl-4-isoxazolyl]penicillin

xo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid