PHARMACOKINETIC AND CLINICAL STUDIES ON CEFPODOXIME PROXETIL DRY SYRUP IN THE FIELD OF PEDIATRICS

Cefpodoxime proxetil (CPDX-PR, CS-807) is a new oral cephem derivative drug in which carboxylic acid was esterified to the 4-position of CPDX (oxime type cephem antibiotic). CPDX-PR is hydrolyzed mainly with esterase in intestinal wall and CPDX exists as an active form in body fluid. While there are numerous study reports using CPDX-PR in tablet forms in Japan, the dry syrup formula for pediatric use was newly developed. The dry syrup of CPDX-PR was orally administered 20 minutes after meal to the 6 boys of ages from 8 years and 1 month to 10 years and 10 months, with doses of 3 and 6 mg/kg, respectively, for 3 cases each. Serum concentrations and urinary concentrations and recovery rate of the drug were investigated. In addition to the above, the clinical and bacteriological studies were performed in a total of 105 cases consisting of children with ages ranging from 2 months to 11 years and 8 months, upon administering an average dose of 3.4 mg/kg, 3 to 4 times per day (96 cases of 3 times and 9 cases of 4 times). The 105 cases included 13 cases of pharyngitis, 21 cases of tonsillitis, 4 cases of acute bronchitis, 6 cases of pneumonia, 1 case of pleurisy, 13 cases of scarlet fever, 41 cases of urinary tract infection, 3 cases of posthitis and 3 cases of bacillary dysentery. Drug sensitivity test was performed for the following strains:(i) Strains retained by our department; 52 strains of Streptococcus pyogenes, 18 strains of Streptococcus agalactiae, and 11 strains of Bordetella pertussis, and (ii) strains isolated from cases to which CPDX-PR was administered; 2 strains of Staphylococcus aureus, 8 strains of S. pyogenes, 2 strains of Haemophilus influenzae, 10 strains of Escherichia coli, and 1 strain of Proteus mirabilis. Drug sensitivities of the strains retained by our department were tested with the inoculum sizes of 108 and 106 cfu/ml for R-3746 (Na-salt of CPDX), cefaclor (CCL), cephalexin (CEX), amoxicillin (AMPC), and methicillin (DMPPC), and those against strains separated from the cases to which CPDX-PR was administered were tested with the same inoculum sizes for R-3746, CCL, CEX, cefadroxil, ampicillin (ABPC), DMPPC and cloxacillin (MCIPC). Adverse reactions and abnormal clinical laboratory test results were also examined. The results obtained are summarized as follows. 1. In both of the dosage level groups of 3 and 6 mg/kg, average serum concentrations of CPDX reached their peaks at 2 hours after administrations and the peak levels of the 2 g