Abstract
Ex vivo
placental perfusion experiments are important in
understanding the quantity and mechanisms of xenobiotic transport to the fetus
during pregnancy. Our study demonstrates that paclitaxel and antipyrine
concentrations in placental perfusion medium containing physiological
concentrations of human serum albumin during pregnancy (30 mg/mL) can be
quantified by RP-HPLC and UV detection. A liquid-liquid extraction method was
developed for the quantification of paclitaxel and celecoxib (internal standard)
from perfusion medium. Antipyrine, which is a necessary marker in placental
perfusions for determining the validity of experiments and calculating the
clearance index of xenobiotics, was also analyzed by HPLC and UV detection.
Antipyrine concentrations were determined by HPLC after precipitating the
perfusion medium in acetonitrile and separating the precipitated proteins by
centrifugation. Concentrations were fitted to linear regressions with
R
2
values approaching 1. Lower limits of detection for paclitaxel
and antipyrine were 100 ng/mL and 200 ng/mL, respectively. Both methods
demonstrated high intra-day and inter-day precision and trueness. Additionally,
the use of these methods was demonstrated in a placental perfusion experiment
using Taxol
®
(paclitaxel dissolved in Cremophor-EL). The fetal
transfer rate of Taxol was 6.6% after 1 hour.