[Bacteriological, pharmacokinetic and clinical studies on cefpodoxime proxetil in the pediatric field]

In bacteriological, pharmacokinetic and clinical studies of cefpodoxime proxetil (CPDX-PR, CS-807), the following results were obtained: 1. Antibacteriological activity Antibacteriological activity of R-3746 (Na-salt of cefpodoxime), cefaclor (CCL), cephalexin, cefroxadine (CXD), cefazolin (CEZ), cephalothin (CET) and amoxicillin (AMPC) were studied against clinical isolated bacteria following as: Staphylococcus aureus (resistant or sensitive of methicillin), Escherichia coli (resistant or sensitive to CEZ), Klebsiella pneumoniae (resistant or sensitive to CEZ), Proteus mirabilis and Enterobacter cloacae. Antibacterial activities of CXD and CET, however, were not tested against methicillin resistant S. aureus (MRSA) or CEZ resistant E. coli and K. pneumoniae. R-3746 showed stronger activities than any of the other oral antibiotics against these strains except S. aureus against which it showed slightly less activity than AMPC. Most frequent MIC values of R-3746 to S. aureus, E. coli, K. pneumoniae and P. mirabilis were 1.56, 0.39, less than or equal to 0.10 and less than or equal to 0.10 microgram/ml, respectively. Against isolated strains of MRSA, MICs of R-3746 were higher than 25 micrograms/ml with 23 strains (77%), which were similar to MIC values of CCL and AMPC against these organisms. MIC values of R-3746 against CEZ resistant E. coli and K. pneumoniae were superior to MICs of other antibiotics, and the MIC50 value was 0.20 micrograms/ml. Against many isolated strains of E. cloacae MIC values of R-3746 were relatively high ranging 0.78 to greater than 100 micrograms/ml. MIC50 of R-3746 against E. cloacae was 12.5 micrograms/ml. 2. Absorption and excretion Serum concentration and urinary excretion of CPDX (the active form of CPDX-PR) were studied upon single oral administration of CPDX-PR at 3 mg/kg, 6 mg/kg (dry syrup) or 100 mg (tablet). The peak of serum concentration of CPDX was attained in 1-6 hours 1-4 hours and 2-6 hours after administration of CPDX-PR at the 3 different dosage levels, and they were 0.99-2.99 micrograms/ml, 4.30-7.05 micrograms/ml and 1.65-2.93 micrograms/ml, respectively. At 8 hours after administration, mean concentrations of CPDX for the 3 groups were 0.31, 0.83 and 0.66 micrograms/ml, respectively. As the average AUC's for the 3 groups were 8.16, 25.97 and 10.79 micrograms.hr/ml, respectively. Urinary recovery rates of CPDX for the 3 groups were 20.9-56.2, 28.3-49.7 and 35.1-50.4%, respectively in the first 8 hours after administration.