Development of a novel microemulsion based on AOT in electrokinetic chromatography for the simultaneous determination of natural and synthetic estrogens

FLOR S.,; TRIPODI V.,; REVELLO L.; CONTIN M.,; LUCANGIOLI S.

Santiago, Chile

Simposio; 13th Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technology; 2007

LACE

Microemulsions are dispersed systems consisting of nanometer size droplets of an inmiscible liquid, stabilized by surfactant and cosurfactant molecules. Due to many potential advantages of microemulsions such as high stability, ability to interact with a wide range of hydrophobic and hydrophilic compounds, transparency and easy preparation, they have been used in capillary electrophoresis (CE) as pseudostationary phases in the electrokinetic chromatography (EKC) mode. Estrogens are steroidal hormones and play important roles at different stages of mammalian development. The most potent naturally occurring estrogen is 17ƒÒ-estradiol (E2), which is interconvertible to the less potent estrogen, estrone (E1). Natural and synthetic estrogens such as estradiol 17-hemisuccinate (E2-HS), etinilestradiol (Et-E2), estradiol 3-benzoate (E2-B) and estradiol 17-valerate (E2-V) are used for the treatment of estrogenic deficiency syndromes, for prevention of osteoporosis and cardiovascular disease in postmenopausal women and for contraception. Traditional methods like GC and HPLC with different detectors have been described for the analysis of various natural and synthetic estrogens. USP official methods report different HPLC systems for the individual determination of E2, E2-V, E3, E1, and Et-E2. The aim of this work was to develop a novel and optimized O/W microemulsion based on AOT and CAPSO buffer for the analysis of E1, E2, E3, E2-HS, Et-E2, E2-B and E2-V by MEEKC. Quantitation of estrogens in pharmaceutical formulations and evaluation of impurities in bulk drugs have also been performed.