title: Determination of steroid hormones in oral contraceptives by high-performance liquid chromatography.
abstract: The aim of this research was to standardize a high-performance liquid chromatographic method for quantitative determination of steroid hormones, like ethinylestradiol (ETE), levonorgestrel (LEVO), and gestodene (GEST), in commercially available oral contraceptives (OCs). The combination ETE-LEVO was analyzed using a LiChrospher 100 RP-8 column (5 microns, 125 x 4 mm) in LiChroCART, with a mobile phase constituted of acetonitrile: water (60:40 v/v). Using the same column, ETE-GEST was analyzed with a mobile phase constituted of acetonitrile:water (50:50 v/v) at pH 7.5 adjusted with 0.02 M ammonium hydroxide. For both methods, a flow rate of 0.8 mL/min was utilized and detection was carried out at 215 nm. All analyses were performed at room temperature (24 +/- 2 degrees C). Calibration curves for ETE-LEVO were obtained using solutions with concentration ranges from 2.40 to 60.0 micrograms/mL (ETE), and from 12.0 to 300.0 micrograms/mL (LEVO). Calibration curves for ETE-GEST were obtained using solutions with concentration ranges from 2.40 to 60.0 micrograms/mL (ETE), and from 9.0 to 160.0 micrograms/mL (GEST). Correlation coefficients obtained were from 0.9999 to 0.9990. Coefficients of variation for samples containing ETE-LEVO were 0.47% and 0.38%, respectively. For samples with ETE-GEST they were 0.39% and 0.44%, respectively. The average recovery for samples with ETE-LEVO was 103.46% and 100.78%, respectively. For samples containing ETE-GEST it was 100.89% and 101.03%, respectively.
authors.affiliation: Departamento de Farmácia, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Caixa Postal 66083, CEP 05315-970, São Paulo, Brazil. ines@usp.br
authors.forename: Maria
authors.initials: M
authors.lastname: Inês
authors.forename: R M
authors.initials: RM
authors.lastname: Santoro
authors.forename: Nájla M
authors.initials: NM
authors.lastname: Kassab
authors.forename: Maya
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Erika R M
authors.initials: ER
authors.lastname: Kedor-Hackmann
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003276:Contraceptives, Oral / Q000737:chemistry*; D045166:Estradiol Congeners / Q000032:analysis*; D004997:Ethinyl Estradiol / Q000032:analysis*; D016912:Levonorgestrel / Q000032:analysis*; D009652:Norpregnenes / Q000032:analysis*; D045167:Progesterone Congeners / Q000032:analysis*
chemical_list: D003276:Contraceptives, Oral; D045166:Estradiol Congeners; D009652:Norpregnenes; D045167:Progesterone Congeners; C033273:Gestodene; D004997:Ethinyl Estradiol; D016912:Levonorgestrel