Determination and co-estimate of the chlormadinone acetate and 17α-ethinyl estradiol in pharmaceutical formulation and drinking water samples by digital derivative spectophotometry

© 2014, Sociedad Chilena de Quimica. All rights reserved.In this work are presented two methods for the simultaneous determination of 17α-ethinylestradiol (EEL) and chlormadinone acetate (CMA) by second order derivative spectrophotometry. The first analytical method proposed is based in the dissolution and extraction of both drugs in acetonitrile. The solution was directly evaluated by second order derivative spectrophotometry with a smoothing factor of 8,000 and a scale factor of 10,000. The determination of EEL and CMA was carried out to 296,6 and 291.8 nm, respectively. The detection limits (3.3 σ criterion) for EEL and CMA were 6.9 × 10-7and 9.8 × 10-8mol / L, respectively. Furthermore, a study of the effect of the excipients containing in the pharmaceutical formulation was included. Polyvidone presents greater tendency to produce interference, but its spectral bands are located between 215 and 240 nm, so these bands do not interferes spectrally in the simultaneous determination o