title: Medroxyprogesterone acetate and estradiol cypionate injectable suspension (Cyclofem) monthly contraceptive injection: steady-state pharmacokinetics.
abstract: BACKGROUND
  Cyclofem is a combined injectable contraceptive, containing medroxyprogesterone acetate (MPA) and estradiol cypionate. The objective was to characterize the steady-state pharmacokinetics (PK) using tandem liquid chromatography/mass spectrometry and compare these data to a previous PK study of this formulation in US women.
  
  
  METHODS
  Fifteen ovulatory, surgically sterile women received three Cyclofem injections, once every 28 days, with serum PK measurements on 23 separate days. Trough levels of estradiol and MPA were obtained on Days 1, 29 and 57, prior to each of the three injections. Steady-state concentrations of MPA and estradiol were assessed during the third treatment month on Days 58, 60, 62, 64, 67, 69, 71, 75, 78 and 85. MPA and serum progesterone levels were measured during the follow-up phase to assess MPA clearance (Days 92, 99, 106, 113, 120, 127, 134 and 141) and return of ovulation (Days 103, 106, 131 and 134).
  
  
  RESULTS
  In the steady state, mean serum MPA concentrations peaked at 1.31 ng/mL at 4.1 days. Mean estradiol levels peaked at 254 pg/mL by 3.3 days. Ovulation was suppressed for at least 77 days post third injection in all but one woman.
  
  
  CONCLUSIONS
  Once monthly injections of Cyclofem resulted in contraceptive levels of MPA without accumulation of hormones, consistent with a previous US study.
authors.affiliation: CONRAD Clinical Research Center, Eastern Virginia Medical School, Norfolk, VA 23507, USA. thurmaar@evms.edu
authors.forename: Andrea
authors.initials: A
authors.lastname: Thurman
authors.forename: Thomas
authors.initials: T
authors.lastname: Kimble
authors.forename: Peter
authors.initials: P
authors.lastname: Hall
authors.forename: Jill L
authors.initials: JL
authors.lastname: Schwartz
authors.forename: David F
authors.initials: DF
authors.lastname: Archer
mesh_terms: D000328:Adult; D001682:Biological Availability; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics / Q000494:pharmacology; D004338:Drug Combinations; D015507:Drugs, Investigational / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics* / Q000494:pharmacology; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology; D005260:Female; D005500:Follow-Up Studies; D006207:Half-Life; D006801:Humans; D007273:Injections, Intramuscular; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D008657:Metabolic Clearance Rate; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D034445:Ovulation Inhibition / Q000187:drug effects; D013535:Suspensions
chemical_list: D003271:Contraceptive Agents, Female; D003692:Delayed-Action Preparations; D004338:Drug Combinations; D015507:Drugs, Investigational; D013535:Suspensions; D004958:Estradiol; C034528:CycloProvera; C007630:estradiol 17 beta-cypionate; D017258:Medroxyprogesterone Acetate