Micellar electrokinetic capillary chromatography as an alternative method for the determination of ethinylestradiol and levo-norgestrel

A method for quantifying of ethinylestradiol (ETE) and levo-norgestrel (LEV) in pharmaceutical products by micellar electrokinetic chromatography (MEKC) is described. The separation was carried out at 25°C and 25 kV, using a 20 mM borate buffer (pH 9.2), 15 mM sodium dodecylsulfate (SDS) in 30% acetonitrile/water (v/v). Under these conditions the analysis takes about 7 min. The method has been applied for quantifying both compounds in six different commercial contraceptives and the proposed method gave good results when compared with a reference liquid chromatographic (LC) method.