BL-S640, a Cephalosporin with a Broad Spectrum of Antibacterial Activity: Bioavailability and Therapeutic Properties in Rodents

The bioavailability and therapeutic properties of BL-S 640 in rodents were compared with those of cephalothin, cephaloridine, and cefazolin after parenteral administration, and cephalexin after oral administration. When given intramuscularly in dosages of 5 to 40 mg/kg, peak concentrations of BL-S 640 in the blood of mice were proportional to dose, but when given orally, they were proportional only up to a dose of 25 mg/kg. After either route of administration, the concentration of BL-S 640 in the blood declined at a slower rate than that of the control compounds. Rats receiving BL-S 640 orally excreted an average of 39% of the drug in the urine. BL-S 640 was highly effective in the treatment of mice infected systemically with a variety of pathogenic bacteria, its therapeutic efficacy in comparison with that of other cephalosporins being frequently in excess of what would have been predicted on the basis of comparative activities in vitro.