Placental transfer of the insulin analog glargine in the ex vivo perfused placental cotyledon model

Objective. The aim was to characterize the transfer of the insulin analog glargine across the placenta using the placental perfusion model. Methods. Placentas were obtained and selected cotyledons were cannulated and dually perfused. Glargine, 50 mU/L (n = 2) and 200 mU/L (n = 1), and a reference marker, antipyrine (50 μg/mL), were added to the maternal circulation. Samples were taken from the maternal and fetal compartments. Results. Glargine was not detected in the fetal compartment. In the maternal compartment, the steady state concentration was 50% lower than the starting concentration. Conclusions. Glargine probably does not cross the human placenta. Reduced maternal steady state concentrations may suggest insulin uptake by the placenta.