title: Determination of levonorgestrel in human plasma by liquid chromatography-tandem mass spectrometry method: application to a bioequivalence study of two formulations in healthy volunteers.
abstract: A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method to determine levonorgestrel in human plasma was developed and fully validated. After hexane-ethyl acetate (70:30, v/v) induced extraction from the plasma samples, levonorgestrel was subjected to LC/MS/MS analysis using electro-spray ionization. The MS system was operated in the selected reaction monitoring mode. Chromatographic separation was performed on a Hypersil BDS C18 column (i.d. 2.1x50 mm, particle size 3 microm). The method had a chromatographic running time of 2.0 min and linear calibration curves over the concentration ranges of 0.25-90 ng/mL for levonorgestrel. The lower limit of quantification of the method was 0.25 ng/mL for levonorgestrel. The intra- and inter-batch precision was 3.7-10.2 and 5.1-12.9%, respectively, for all quality control samples at concentrations of 0.5, 6.0 and 45.0 ng/mL. These results indicate that the method was efficient with a simple preparation procedure and a very short running time (2.0 min) for levonorgestrel compared with those methods reported in the literature and had high selectivity, acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method was successfully used for a bioequivalence study of two tablet formulations of levonorgestrel in healthy volunteers.
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, and Department of Pharmacy the First Affiliated Hospital, Guangzhou 510080, People's Republic of China.
authors.forename: Li-Zi
authors.initials: LZ
authors.lastname: Zhao
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Zhong
authors.forename: Hui-Chang
authors.initials: HC
authors.lastname: Bi
authors.forename: Liang
authors.initials: L
authors.lastname: Ding
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Su
authors.initials: S
authors.lastname: Guan
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Zhi-ying
authors.initials: ZY
authors.lastname: Huang
authors.forename: Min
authors.initials: M
authors.lastname: Huang
mesh_terms: D000328:Adult; D002853:Chromatography, Liquid / Q000379:methods*; D003271:Contraceptive Agents, Female / Q000097:blood / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000097:blood* / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013810:Therapeutic Equivalency
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel