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September 1963

Sodium Oxacillin in Surgical Infections: Clinical Evaluation

Author Affiliations

Assistant Professor Surgery, The Chicago Medical School; Associate, Mount Sinai Hospital; Attending, Hines Veterans Administration Hospital.

Arch Surg. 1963;87(3):507-511. doi:10.1001/archsurg.1963.01310150143032

Doyle and Nayler1 in 1961 chemically coupled the diacetylization of 6-aminopenicillanic acid to 5-methyl-3-phenyl-4-isoxazolecarboxylic acid and produced a colorless, crystalline compound known as sodium oxacillin,* or MPI, or P-12. Its molecular weight is 441.43, and it is extremely stable in its dry state. It is freely soluble in water and in the state of solution may be stable for 24 hours at room temperature. Its most important attribute is that it is acid resistant. This allows it to be used as an oral preparation. It is penicillinase resistant and apparently ten times more active than methicillin against Staphylococcus aureus, coagulase positive. Reports reveal that Staph aureus is inhibited by MPI penicillin in concentrations of 1 mEq or less per milliliter. Its bactericidal end point lies between 2.5 and 5 mg/cc.2 Numerous clinical studies have been carried out which reveal a marked antistaphylococcal activity.3,4 MPI penicillin was a more