Pharmacokinetics of cefprozil in infants and children

Twenty pediatric patients (ages, between 8 months and 8 years) received a single oral dose of cefprozil at levels of 15 and 30 mg/kg of body weight. Cefprozil consists of cis (BMY-28100) and trans (BMY-28167) isomers in an approximately 90:10 ratio. Six plasma samples were collected from each pediatric patient and assayed for drug concentrations. As measured by a microbiological assay, peak concentrations of 11.16 and 15.93 μg of cefprozil per ml occurred at 1 h for patients who received the 15- and 30-mg/kg doses, respectively. The respective mean half-lives of cefprozil were 1.77 and 2.14 h, and the respective mean areas under the curve were 28.05 and 45.28 μg · h/ml for patients who received the 15- and 30-mg/kg doses. When measured by a high-pressure liquid chromatography method, peak concentrations of 12.09 and 18.04 μg of the cis isomer per ml were obtained at 1 h, with mean half-lives of 1.63 and 2.06 h and mean areas under the curve of 30.48 and 49.34 μg · h/ml in patients who received the 15- and 30-mg/kg doses, respectively. For the trans isomer, peak concentrations of 1.16 and 1.63 μg/ml occurred at 1 h, respectively, with mean half-lives of 1.61 and 1.65 h and mean areas under the curve of 2.89 and 4.34 μg · h/ml in patients who received the 15- and 30-mg/kg doses, respectively.