title: Distribution of bupivacaine enantiomers and lidocaine and its metabolite in the placental intervillous space and in the different maternal and fetal compartments in term pregnant women.
abstract: The aim of this study is to determine the concentrations of lidocaine and its metabolite, monoethylglycine xylidide (MEGX), and of the enantiomers of bupivacaine in maternal and fetal compartments. Ten healthy pregnant women were submitted to epidural anesthesia. Drug concentrations were determined in the maternal vein, fetal umbilical artery and vein, and the placental intervillous space. The highest concentrations of the bupivacaine enantiomers lidocaine and of lidocaine and of its MEGX metabolite were detected in maternal plasma and in the placental intervillous space. The placental transfer was 33% for the (+)-(R)-bupivacaine enantiomer and 31% for the (-)-(S)-bupivacaine enantiomer. For lidocaine and its MEGX metabolite, respective placental transfers were 60% and 43%. Lidocaine concentration in the fetal umbilical vein was 1.46 times higher than in the fetal umbilical artery. The highest concentrations of lidocaine and its metabolite and of the enantiomers of bupivacaine were detected in the placental intervillous space. The higher lidocaine concentrations in the fetal umbilical vein than in the fetal umbilical artery suggest that there was tissue uptake of the drug or drug metabolization by the fetus.
authors.affiliation: Departamento de Ginecologia and Obstetrícia-8° andar, Hospital das Clínicas-Faculdade de Medicina de Ribeirão Preto, Av Bandeirantes, 3900-Campus da USP, 14049-900 Ribeirão Preto, SP, Brasil. lbdmedi@msn.com
authors.forename: Luciana
authors.initials: L
authors.lastname: de Barros Duarte
authors.forename: Elaine Cristine
authors.initials: EC
authors.lastname: Dantas Móises
authors.forename: Ricardo Carvalho
authors.initials: RC
authors.lastname: Cavalli
authors.forename: Vera Lucia
authors.initials: VL
authors.lastname: Lanchote
authors.forename: Geraldo
authors.initials: G
authors.lastname: Duarte
authors.forename: Sérgio Pereira
authors.initials: SP
authors.lastname: da Cunha
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural / Q000379:methods; D000773:Anesthesia, Obstetrical / Q000379:methods; D000779:Anesthetics, Local / Q000737:chemistry / Q000493:pharmacokinetics*; D002045:Bupivacaine / Q000737:chemistry / Q000493:pharmacokinetics*; D002824:Chorionic Villi / Q000378:metabolism; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D013237:Stereoisomerism; D014018:Tissue Distribution; D014469:Umbilical Arteries / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; C001173:monoethylglycinexylidide; D002045:Bupivacaine