Bacteriological, pharmacokinetic and clinical studies on sulbactam/cefoperazone in the pediatric field

Bacteriological and clinical effect of a newly developed SBT/CPZ in the treatment for pediatric patients was assessed by a study group consisting of 15 institutions. The results were as follows. Antibacterial effect Susceptibility studies were performed with 93 clinical isolates. The MIC of SBT/CPZ was one-tube inferior or almost similar to that of CPZ in susceptible organisms. In CPZ-resistant organisms at the inoculum of 10(8) cells/ml, however, SBT/CPZ was much superior to CPZ on the basis of the MIC. When the MIC of SBT/CPZ was compared to that of CPZ in 27 strains which have high beta-lactamase-producing activity, it was found that many of CPZ-resistant organisms were susceptible to SBT/CPZ. Serum concentration and urinary excretion The serum concentrations of SBT and CPZ were 33.2 micrograms/ml, respectively at 15 minutes after 20 mg/kg SBT/CPZ was administered by intravenous bolus injection, and those of SBT and CPZ, 51.0 micrograms/ml and 108.3 micrograms/ml, respectively following 40 mg/kg SBT/CPZ therapy. The serum concentrations of CPZ were 2.1-2.4 times as high as those of SBT. The concentrations were dose-related. The half-lives of SBT and CPZ following 20 mg/kg SBT/CPZ administration were 0.94 hour and 1.50 hours, respectively, and those following 40 mg/kg SBT/CPZ were 0.95 hour and 1.53 hours, respectively. There was no significant difference between 20 mg/kg and 40 mg/kg administrations. When compared between SBT and CPZ, CPZ had slightly longer half-lives. At the termination of 1 hour drip infusion of 20 mg/kg SBT/CPZ, the serum concentrations of SBT and CPZ were 16.7 micrograms/ml and 40.1 micrograms/ml, respectively. In the case of 40 mg/kg, the levels of SBT and CPZ were 38.6 micrograms/ml and 94.9 micrograms/ml, respectively. The concentrations were found to be dose-related as were following intravenous bolus injections. The SBT half-lives obtained after 20 mg/kg and 40 mg/kg SBT/CPZ administrations were 1.39 hours and 0.89 hour, respectively; those of CPZ, 2.00 hours and 1.44 hours, respectively. The highest urinary concentration occurred 0-2 hours after intravenous bolus injections of 20 mg/kg or 40 mg/kg SBT/CPZ. Urinary excretion of SBT over 6 hours was 60.0% and 67.7%, and that of CPZ, 21.2% and 25.0%, indicating higher urinary excretion for SBT. When 20 mg/kg SBT/CPZ or 40 mg/kg was administered over 1 hour by drip infusion, urinary excretion became the highest at 1-3 hours after administration. Urinary excretion of SBT over 7 hours following 20 mg/kg and 40 mg/kg SBT/CPZ was 68.8% and 80.3%, respectively, and that of CPZ, 24.4% and 27.3%. The results were similar to those observed following intravenous bolus injections.