High-pressure liquid chromatographic analysis of estrogens in pharmaceuticals by measurement of their dansyl derivatives.

A high-pressure liquid chromatographic method is described for the analysis of estrogens in pharmaceutical tablet and injectable dosage forms. In general, the estrogens are isolated, an internal standard is added, the dansyl derivatives are formed, and the dansyl estrogen solution is injected into a liquid chromatograph. Linear response is experienced between the mass of estrogen and the ratio of the estrogen peak height to the internal standard peak height, using a microparticle silica column and chloroform--n-heptane mobile phases. With fluorometric measurement, limits of detectability for ethinyl estradiol and estradiol were 0.04 and 0.05 ng, respectively. Methyltestosterone, an androgen in combination with ethinyl estradiol, was analyzed simultaneously. Commercial pharmaceutical preparations containing estrone, ethinyl estradiol, and estradiol were analyzed by the proposed method. The results indicate the method to be sensitive, reasonably precise (less than 2%), and accurate in the analysis of estrogen in dosage forms.