title: Positron emission tomography in studies on fetomaternal disposition of opioids.
abstract: The noninvasive radiotracer technique, positron emission tomography, has been applied in studies on the transfer of drugs from mother to fetus in Rhesus monkeys. 11C-labelled morphine or heroin was administered intravenously to pregnant monkey and the radioactivities with time were measured in the placenta, fetal liver and maternal blood. The information from the 11C-morphine experiment was supplemented with data from the simultaneous administration of 14C-morphine followed by the analysis of unchanged drug and metabolites in maternal blood and also in one sample from fetal blood. In placenta, 11C-morphine and 11C-heroin rapidly reached high radioactivities already within the first few minutes after administration. The transfer of 11C-morphine-derived radioactivity to the fetus was also rapid, although there was a lag-time in relation to the placental uptake. The elimination rate of the radioactivity was fast from the blood, placenta and the fetal liver and in plasma there was a rapid appearance of conjugated morphine metabolites. The fetal plasma concentration of morphine was twice that in maternal plasma 100 min after injection. The transfer of 11C-heroin-derived radioactivity to the fetus was even faster than was the elimination of radioactivity. The plasma kinetics of morphine in the mother and fetus was simulated in a compartment flow model and simulated concentrations agreed well with measured values.
authors: Hospital Pharmacy, University of Uppsala, Sweden.
authors: P
authors: P
authors: Hartvig
authors: B S
authors: BS
authors: Lindberg
authors: A
authors: A
authors: Lilja
authors: H
authors: H
authors: Lundqvist
authors: B
authors: B
authors: Långström
authors: A
authors: A
authors: Rane
mesh_terms: D000818:Animals; D005260:Female; D005333:Fetus / Q000378:metabolism; D003932:Heroin / Q000378:metabolism; D008253:Macaca mulatta; D008431:Maternal-Fetal Exchange; D009020:Morphine / Q000493:pharmacokinetics; D009294:Narcotics / Q000493:pharmacokinetics*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D014055:Tomography, Emission-Computed
chemical_list: D009294:Narcotics; D003932:Heroin; D009020:Morphine