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Updated: Jul 8, 2026

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model
Published on: June 18, 2013
Transfer of methadone across the dually perfused preterm human placental lobule
Tatiana N Nanovskaya1, Ilona A Nekhayeva, Gary D V Hankins
1Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555-0587, USA.
Objective:
The objective of the study was to determine the effect of gestational age and P-glycoprotein expression on transplacental transfer of methadone.
Study Design:
Dual perfusion of placental lobule was utilized. Methadone (200 ng/mL) and its [3H]-isotope were cotransfused from the maternal-to-fetal circuit with the marker compound antipyrine (20 microg/mL) and its [14C]-isotope. Concentration of the drugs in trophoblast tissue and both circuits was determined by liquid scintillation spectrometry.
Results:
Fetal transfer rate of methadone in preterm placentas was 19 +/- 5.8%, and in term placentas it was 31 +/- 9.7% (P < .01). Clearance index of methadone in preterm placentas (0.57 +/- 0.2) was lower than in term placentas (0.95 +/- 0.3, P < .01). P-glycoprotein expression was higher in preterm than term placentas.
Conclusion:
The ex vivo transfer of methadone across preterm placentas is 30% lower than in term placentas.
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