Albumin-dependent digoxin transfer in isolated perfused human placenta

Objective: To determine the effects of albumin (BSA) concentration in perfu sion medium on digoxin transfer in isolated perfused human placental cotyle don. Study de Isolated placental cotyledons from 13 normal human placentas were dually perfused after cannulating artery and vein of the chorionic pla te and piercing 4 catheters through the corresponding basal plate with M199 medium enriched with BSA and glucose. Flow rates were 12 and 6 ml/min in t he maternal and fetal circuits, respectively. Digoxin was added to the mate rnal reservoir at a final concentration of 5.51 +/- 1.00 ng/ml. BSA in mate rnal and fetal perfusate was kept at 3 concentrations: 1, 3 and 5 mg/ml (Gr oups 1, II, III). Transplacental passage of digoxin was calculated from rep eated fetal and maternal perfusate samples collected over 3 hours in the 3 groups. Digoxin levels were measured by FPIA (TDx, Abbott). Results: There was no transfer of digoxin from the maternal to fetal compartment when the concentration of BSA was I mg/ml. Increasing the concentration of BSA led t o a substantial increase in the transfer of digoxin to the fetal compartmen t. Steady state levels of digoxin in the fetal compartment were 0.61 +/- 0. 19 ng/ml at 3 mg/ml of BSA. Conclusion: Maternal and fetal serum concentrat ion of BSA affect digoxin transfer in isolated perfused human placentas. Th ree mg/ml are considered to be the optimal albumin concentration.