Analog computer simulation of maternal - fetal transfer of cefazolin

Cefazolin concentration-time data after normal vaginal delivery were obtained for maternal serum, placenta, umbilical cord blood, and amniotic fluid. After normalizing of the data, concentration-time profiles were generated for each sampling compartment. A pharmacokinetic model for analog computer simulation was developed. Multiple dosing simulation suggests a higher accumulation of cefazolin in fetal than in maternal blood, and a slow accumulation in amniotic fluid, which acts as a depot or storage. The drug is transferred diaplacentally; paraplacental transfer seems to be absent for cefazolin.