title: Pharmacology and placental transport of 17-hydroxyprogesterone caproate in singleton gestation.
abstract: OBJECTIVE
  The purpose of this study was to estimate pharmacokinetic parameters and to evaluate placental transport of 17-hydroxyprogesterone caproate (17-OHPC) in singleton gestation.
  
  
  METHODS
  Sixty-one women who received weekly injections of 17-OHPC underwent 2 pharmacokinetic studies at 20 + 0 to 24 + 6 weeks' gestation (study 1) and 31 + 0 to 34 + 6 weeks' gestation (study 2); daily blood samples were obtained between injections. In 18 women, blood samples were obtained over a 28-day period beyond the last injection (extended study). Maternal and/or cord blood were obtained at delivery.
  
  
  RESULTS
  The half-life (median ± SD) of 17-OHPC was 16.2 ± 6 days. Concentrations of 17-OHPC were higher during study 2 than during study 1. Body mass index affected maternal 17-OHPC concentrations. Cord:maternal 17-OHPC concentration ratios averaged 0.2; 17-OHPC was detectible in cord plasma 44 days after the last maternal injection.
  
  
  CONCLUSIONS
  The apparent half-life of 17-OHPC is long, and pharmacokinetic parameters vary widely between subjects and are affected by maternal body mass index. The drug crosses the placental barrier.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Shringi
authors.initials: S
authors.lastname: Sharma
authors.forename: Raman
authors.initials: R
authors.lastname: Venkataramanan
authors.forename: Gary D
authors.initials: GD
authors.lastname: Hankins
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Mary F
authors.initials: MF
authors.lastname: Hebert
authors.forename: Jason G
authors.initials: JG
authors.lastname: Umans
authors.forename: Thomas
authors.initials: T
authors.lastname: Benedetti
authors.forename: Donald
authors.initials: D
authors.lastname: Mattison
authors.forename: Anne
authors.initials: A
authors.lastname: Zajicek
authors.forename: Dawn
authors.initials: D
authors.lastname: Fischer
authors.forename: Aimee
authors.initials: A
authors.lastname: Jackson
mesh_terms: D000077713:17 alpha-Hydroxyprogesterone Caproate; D000328:Adult; D001692:Biological Transport / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D006908:Hydroxyprogesterones / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011372:Progestins / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D055815:Young Adult
chemical_list: D006908:Hydroxyprogesterones; D011372:Progestins; D000077713:17 alpha-Hydroxyprogesterone Caproate