The concentrations of ceftazidime and thiopental in maternal plasma, placental tissue and amniotic fluid in early pregnancy.

Studies on the transfer of drugs from mother to fetus in the first trimester of pregnancy are important because of the possible teratogenic effect on the fetus as well as possible therapeutic effect on both sides of the feto-maternal barrier. The purpose of this study was to measure drug concentrations in maternal plasma, placental tissue and amniotic fluid in a group of first-trimester abortion patients. Ceftazidime and thiopental were chosen as experimental drugs. The analyses were done with high pressure liquid chromatography. The penetration of ceftazidime into placental tissue and amniotic fluid was 20.6 and 2.2% from 1 to 4 h after drug administration. The corresponding values for thiopental were 54.3-71 and 1.5-7.4% from 5 to 15 min after drug administration, indicating a rapid transfer of both drugs across the feto-maternal barrier during this period in pregnancy.