Transplacental transfer of 2-naphthol in human placenta

OBJECTIVE To determine the transfer of 2-naphthol (2-NPH) in fullterm human placental tissues. METHODS Six placentas were studied. The ex-vivo dual closed-loop human placental cotyledon perfusion model was used. 2-NPH was added to the perfusate in the maternal compartment. Samples were obtained from the maternal and fetal up to 360 min measuring. RESULTS The mean fetal weight was 2880 ± 304.2 g. Mean perfused cotyledon weight was 26.3 (±5.5) g. All unperfused placental tissue samples contained NPH with a mean level of 7.98 (±1.73) μg\g compared to a mean of 15.58 (±4.53) μg\g after 360 min perfusion. A rapid drop in maternal 2-NPH concentration was observed; from 5.54 μg\g in the first 15 min and 13.8 μg\g in 360 min. The fetal side increased from 0.65 μg\g in the initial 15 min to 1.5 μg\g in 360 min. The transfer rate of NPH was much lower than that of antipyrine. CONCLUSION 2-NPH has the ability to rapidly across the placenta from the maternal to the fetal compartment within 15 min. The placenta seems to play a role in limiting the passage of 2-NPH in the fetal compartment.