Placental passage of angiotensin-converting enzyme inhibitors.
ABSTRACT Placental passage of the angiotensin-converting enzyme inhibitors temocapril and enalapril was investigated in a placental perfusion model.
In an open system a placental lobe was perfused on both the maternal and the fetal side with a blood-free medium containing the test substances plus a reference substance on the maternal side. Six placentas were perfused with temocapril and five with enalapril. The drugs were measured by gas chromatography-mass spectrometry.
Both angiotensin-converting enzyme inhibitors crossed the human placenta in the maternal-fetal direction in similar quantities. Temocapril showed the same pharmacokinetic characteristics as enalapril.
This was the first study to quantify the placental transfer of angiotensin-converting enzyme inhibitors. These antihypertensive agents should not be taken during pregnancy, to avoid any potential hazards to the fetus.
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ABSTRACT: QUESTION: One of my 35-year-old pregnant patients has been treated with enalapril for primary hypertension. She learned she was pregnant at 11 weeks' gestation. I read somewhere that angiotensin-converting enzyme (ACE) inhibitors can cause malformations. What advice do you give to Motherisk callers? ANSWER: Most published studies have failed to show an effect of ACE inhibitors on congenital malformations. A recent systematic review and meta-analysis conducted by Motherisk does not suggest increased fetal risk of malformations. However, ACE inhibitors should be avoided in late pregnancy, as they might cause renal failure and acalvaria in the baby.Canadian family physician Medecin de famille canadien 01/2012; 58(1):49-51. · 1.19 Impact Factor
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ABSTRACT: Enalapril is an antihypertensive drug of the class of angiotensin-converting enzyme inhibitors (ACEI) used in pregnancy for treatment of pre-existing or pregnancy-induced hypertension. The use of ACE inhibitors (drugs that act directly on the renin-angiotensin system) during the second and third trimester of pregnancy in humans is associated with specific fetal and neonatal injury. The syndrome, termed “ACEI fetopathy” in humans, does not appear to have a similar counterpart in experimental animals. The present paper reviews pharmacokinetic and pharmacodynamic aspects of enalapril that are physiologically important during pregnancy and intrauterine development in humans and in experimental animal species with the aim of better understanding the comparability of the manifestations of enalapril developmental toxicity in animals and humans. The human fetus is at a disadvantage with regard to in utero enalapril exposure in comparison to some of the animal species for which gestational pharmacokinetic data are available. Important reasons for the higher vulnerability of the human fetus are its accessibility by enalapril and the earlier (relative to animal species) intrauterine development of organ systems that are specific targets of ACEI pharmacologic effect (the kidney and the renin-angiotensin system). In humans, these systems develop prior to calcarial ossification at the end of first trimester of pregnancy. The specific pharmacodynamic action of enalapril on these systems during fetal life is the chief determinant of the etiology and pathogenesis of ACEI fetopathy in humans. In contrast, in most of the studied animal species, these target systems are not developed until close to term when the fetus is relatively more mature (and therefore less vulnerable), so that the window of vulnerability is narrower in comparison to the human. Among animal species, the best concordance in fetal pharmacodynamics to the human is seen in the rhesus monkey, but further studies are necessary to determine if similar developmental pathology is induced in this animal model upon repeated administration of the drug during the relevant period of intrauterine development. Animal-human concordance of developmental toxicity is least likely in the rat because of greater disparities in enalapril availability to the fetus and the relative development of the kidney and skeletal ossification compared to that in humans.Reproductive Toxicology 01/2001; · 2.77 Impact Factor
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ABSTRACT: This work describes a novel method of data transmission by means of polarisation shift keying. It analyses the system performance in terms of S/N ratio and defines the required antenna cross polarisation performance to achieve an acceptable S/N ratio. A theoretical analysis of antenna cross polarisation performance is provided. This analysis predicts a dependence of cross polarisation upon antenna substrate and angle of observation which is supported by experimental evidence. This work has also enabled accurate design criteria to be successfully applied to the fabrication of a dual feed circular disc antenna for polarisation shift keying at 2.45GHz.01/1989;