Cloxacillin, a new oral synthetic penicillin: Comparisons with oxacillin

With antibiotics, as with other drugs, minor alterations in chemical structure are often responsible for significant differences in pharmacologic activity. In the present study, cloxacillin, differing in the addition of a single chloride atom, gave much higher blood levels following oral administration than those obtained with oxacillin. Other characteristics of the two compounds, including in vitro activity, development of resistance, and binding to serum proteins, were remarkably similar for the two compounds. The significantly higher blood levels obtained with cloxacillin suggest that this compound represents a useful advance in the oral therapy of infectiOns caused by penicillin G‐resistant staphylococci.