A new semi-synthetic penicillin, Nafcillin (NF-PC), which has been developed by Wyeth Laboratories, is said to possess a potent antibacterial activity against Gram-positive bacteria, particularly against penicillin resistant strains of Staphylococci. Studies on
in vitro antibacterial activity, absorption and excretion as well as clinical trials of Nafcillin have been carried out, and the results obtained are summarized as follows :
1)
In vitro antibacterial activity
Forty nine strains of
Staphylococcus aureus isolated recently from infectious lesious were tested for their susceptibility to NF-PC in comparison with DMP-PC and MPI-PC, and found that 92% of tested strains were sensitive to NF-PC at the concentration below 0.2 mcg/ml and no strain grew in the media containing more than 3.2 mcg/ml. The susceptibility of these strains to NF-PC was two or four times higher than that to DMP-PC, while antibacterial activity of MPI-PC proved to be as potent as NF-PC.
2) Absorption and excretion
Drug concentration in blood reached to peak level, being 1.88 mcg/ml, at an hour after oral administration of 500 mg of NF-PC to fasted subjects, and declined to 0.38 mcg/ml after four hours. Urinary recovery rate during the first 6 hours was calculated to be 2 to 10%. The penetration of the antibiotics into pus which is tested in clinical cases is a half to one-fifth of maximum blood level. In bile from clinical cases, the concentration was estimated 50 times as high as that of blood level.
3) Clinical trials
Of 20 cases of surgical infection, treated with NF-PC, 3 cases responded excellently, 13 well, 3 poorly and in one the effectiveness remained undecided. No particular side effects were observed.
抄録全体を表示