Pediatric Cefazolin PK Study

This is a multiple-center, open-label, PK study of cefazolin in children aged 10 to 12 years (inclusive) receiving 1g or 2 g of cefazolin delivered via the DUPLEX® drug delivery system for surgical prophylaxis. Surgery should be expected to last no longer than 3 hours. If a second dose of cefazolin is required, the subject will be excluded from the PK analysis and additional subjects will be enrolled if necessary to obtain eight evaluable subjects. The surgical procedures may be performed in an outpatient or inpatient setting but subjects must be available to complete the planned 8-hour PK sampling as noted below. Study drug will be administered by continuous infusion over a 30-minute period using an infusion pump. Based on weight at Day 1(Day of Surgery) (unless a weight assessment was obtained within the previous seven days that by physician judgment is felt to represent a stable weight and not have the potential to change such that the subject dose may be affected). Subjects weighing ≥25 kg and \< 50 kg will receive the 1g dose. Subjects weighing ≥ 50 kg and ≤ 85 kg will receive the 2g dose. Dose groups will not be balanced by age or gender. The weight-based dosage regimen that will be employed for this study has been selected to assure that subjects will receive a dose between 20 and 40 mg/kg body weight, based on Monte Carlo simulations using adult PK data, which is consistent with current practice. Blood samples for determination of PK of cefazolin will be drawn at the following times: 15 minutes before the start of infusion (baseline), at the end of infusion, 15 and 30 minutes and 1 hour, 2 hours, 3 hours, 6 hours, and 8 hours after the end of the infusion for a total of nine blood samples. Safety will be assessed by monitoring adverse and serious adverse events based on patient history, vital signs, and physical examination. Follow-up phone calls will be placed to each subject one week post treatment to assess adverse events (AEs) and well-being.