Transfer of ciprofloxacin, ofloxacin and levofloxacin across the perfused human placenta in vitro.

OBJECTIVE: To investigate the transfer of therapeutically important fluoroquinolones: ciprofloxacin, ofloxacin and levofloxacin, through the isolated perfused human placenta, from the maternal to the fetal compartment. STUDY DESIGN: Isolated placental cotyledons from normal human term placentae were dually perfused with M199 medium enriched with 3g/l bovine serum albumin and 1g/l glucose. Perfusion rates were 12 and 6 ml/min in the maternal and fetal circulation, respectively. Maternal and fetal closed circulation was used to evaluate steady-state concentrations and transplacental gradient formation. Eighteen placentae were used in our study: six for each experiment with ciprofloxacin, ofloxacin and levofloxacin were added to the maternal circulation. Samples were collected from the maternal and fetal compartments. Antipyrine was used as a reference drug that crosses the placenta by simple diffusion. The concentrations of ciprofloxacin, ofloxacin, levofloxacin and antipyrine were measured by specific HPLC (high performance liquid chromatography) methods. Results are presented as mean+/-S.D. RESULTS: In all the placentae, ciprofloxacin, ofloxacin, levofloxacin crossed the placenta from the maternal to the fetal compartment. The mean transplacental transfer percent of ciprofloxacin was 3.2+/-0.7% and the transplacental transfer index, the ratio of transplacental transfer between ciprofloxacin and antipyrine was 0.34+/-0.12. The mean transplacental transfer percent of ofloxacin was 3.7+/-2.4% and the transplacental transfer index was 0.33+/-0.3. The mean transplacental transfer percent of levofloxacin was 3.9+/-1.5% and the transplacental transfer index was 0.34+/-0.2. CONCLUSIONS: Only a small fraction of ciprofloxacin, ofloxacin and levofloxacin passed from the maternal to the fetal compartment. This fraction is significantly smaller compared to antipyrine. This may indicate that there is a barrier to the transport of fluoroquinolones in human placenta.

Transfer of insulin lispro across the human placenta.

Our in vitro perfusion study confirms the result of the Boskovic et al., that insulin lispo is not crossing the human placental membranes at low concentrations. In our study maternal steady state concentration reached 48 +/- microU in the maternal artery and 28 +/- 1 microU in the maternal vein, while in the fetal site insulin lispo was not detected. However, the concentration of insulin lispo in placental tissue was 1836 +/- 220 microU.

New aspects in placental drug transfer.

The human placenta is the interface between the mother and fetus in the uterus. Until recently it was generally believed that the uterus provides a protective environment for the fetus. It is now accepted that any chemical substance, including any therapeutic agent, administered to a mother is able to permeate across the placental barrier. Unfortunately, the placental transfer of substances and their distribution in the placenta is not well established. Understanding the structure of placental transporters and their function may serve as the ideal tool for drug development and the cure of mother and fetus during pregnancy.