Fundamental studies of transferred concentration of piperacillin into maternal serum, umbilical cord serum and amniotic fluid

In order to evaluate the clinical efficacy of piperacillin (PIPC) in the obstetrical field, 1 g of PIPC was intravenously administered to 45 normal term gravidas and PIPC concentrations in maternal serum, umbilical cord serum and amniotic fluid were determined. Fifty-three samples of maternal serum, 45 samples of umbilical cord serum and 44 samples of amniotic fluid were obtained at amniotomy and delivery. The results of these studies are summarized as follows. 1. Mean biological half life of PIPC in maternal serum administered to term gravidas was 61.43 minutes. 2. Placental transfer of PIPC concentration into umbilical cord serum was about 71% of maternal serum concentration after 1 hour. 3. There was no prominent difference in the PIPC concentrations of the amniotic fluid between the ruptured and unruptured cases. Fast transfer of PIPC into the amniotic fluid was recognized, such as 1 case was already raised to 4.3 micrograms/ml of PIPC in the amniotic fluid at 1 hour after administration. 4. The maternal serum and amniotic fluid concentration had a contrary relationship, and crossed each other at ca. 5 micrograms/ml of concentration after 2 hours and 50 minutes. Over a period of 6 hours and 20 minutes, the amniotic fluid concentration gradually increased.