“…Dual perfusion of a single placental lobule ex vivo is the only experimental model to study human placental transfer of substances in organized placental tissue and theoretically may be able to more reliably predict fetal exposure compared to other experimental methods ( Table 1 ). Although tedious, the placental perfusion model has proven useful in studying both endogenous and exogenous substrates, such as amino acids, hormones, electrolytes, viruses, therapeutics, and illicit drugs 3 , 4 , 5 , 6 . This model allows simultaneous investigation of many properties that can influence placental drug transfer, such as physiochemical properties (size, the negative logarithm of the acid dissociation constant (pK a ), and lipophilicity) and pharmacokinetic factors (active transport, placental binding, and metabolism).…”