title: Simultaneous determination of ethinylestradiol and levonorgestrel in oral contraceptives by derivative spectrophotometry.
abstract: A method for determining ethinylestradiol (ETE) and levonorgestrel (LEV) in mixtures by first-derivative spectrophotometry is described. The procedure does not require any separation step. Measurements are made at the zero-crossing wavelengths and the calibration graphs are linear up to 26 and 33 micrograms ml-1 of ETE and LEV, respectively. The method was applied to the determination of both compounds in five different Spanish commercial low-dose oral contraceptives. Similar results were obtained by an HPLC method.
authors.affiliation: Departamento de Química Analítica y Tecnología de Alimentos, Facultad de Ciencias, Universidad de Castilla-La Mancha, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Berzas
authors.forename: J
authors.initials: J
authors.lastname: Rodríguez
authors.forename: G
authors.initials: G
authors.lastname: Castañeda
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003278:Contraceptives, Oral, Hormonal / Q000737:chemistry*; D045166:Estradiol Congeners / Q000032:analysis*; D004997:Ethinyl Estradiol / Q000032:analysis*; D016912:Levonorgestrel / Q000032:analysis*; D045167:Progesterone Congeners / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013053:Spectrophotometry
chemical_list: D003278:Contraceptives, Oral, Hormonal; D045166:Estradiol Congeners; D045167:Progesterone Congeners; D004997:Ethinyl Estradiol; D016912:Levonorgestrel