title: Simultaneous determination of levonorgestrel and two endogenous sex hormones in human plasma based on LC-MS/MS.
abstract: BACKGROUND
  Levonorgestrel (LNG) is a commonly used emergency contraceptive which can effect sex hormone levels in female blood. The objective of this study was to develop and validate a specific and sensitive LC-MS/MS method for monitoring endogenous sex hormone levels (17β-estradiol and progesterone) in female plasma after administration of LNG. Results & methodology: The method was developed, optimized and validated according to the EMA guideline. Assay validation met all the criteria, including good linearity in the range of 0.1-20 ng/ml for 17β-estradiol, as well as 0.2-30 ng/ml for LNG and progesterone.
  
  
  CONCLUSIONS
  The method has been preliminarily applied to explore the variation trend of sex hormone levels in healthy Chinese female volunteers' plasma after oral administration of 1.5 mg LNG tablet. With LNG absorption into plasma, progesterone and estradiol levels descended rapidly, and maintained at low levels in the onset time.
authors.affiliation: Key Laboratory of Drug Quality Control & Pharmacovigilance (China Pharmaceutical University), Ministry of Education, Nanjing 210009, China.
authors.forename: Rulin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Key Laboratory of Drug Quality Control & Pharmacovigilance (China Pharmaceutical University), Ministry of Education, Nanjing 210009, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Key Laboratory of Drug Quality Control & Pharmacovigilance (China Pharmaceutical University), Ministry of Education, Nanjing 210009, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Drug Quality Control & Pharmacovigilance (China Pharmaceutical University), Ministry of Education, Nanjing 210009, China.|State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Zunjian
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage / Q000097:blood*; D057230:Limit of Detection; D011374:Progesterone / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D003271:Contraceptive Agents, Female; D011374:Progesterone; D004958:Estradiol; D016912:Levonorgestrel
keywords: LC–MS/MS; bioanalytical; emergency contraceptive; endogenous sex hormones; specificity