Transfer of metformin across the dually perfused human placental lobule

Objective: The purpose of this study was to determine the transfer characteristics of metformin across placentas that were obtained from uncomplicated pregnancies and from patients with gestational diabetes mellitus. Study design: The technique of dual perfusion of placental lobule was used. Metformin, 5 μg/mL and its [ ¹⁴C]-isotope were co-transfused with the marker compound antipyrine, 20 μg/mL and its [ ³H]-isotope from the maternal to fetal circuit. The drug content in both circulations and placental tissue was determined by liquid scintillation spectrometry. Results: The transfer of metformin across term human placentas that were obtained from uncomplicated pregnancies was rapid and was not different from that in placentas that were obtained from patients with gestational diabetes mellitus. Metformin is distributed between the maternal and fetal circuits, with reliable amounts retained by the tissue. Conclusion: In an ex vivo model system, metformin was transferred readily from the maternal to fetal circuit across placentas that were obtained from uncomplicated pregnancies and pregnancies with gestational diabetes mellitus.