HPLC analysis of pharmaceutical estrogens in raw materials and dosage forms

The use of HPLC with fluorescence detection (lambda ex = 280 nm; lambda em = 410 or 312 nm) in combination with a postcolumn on line photochemical derivatization was investigated for the analysis of conjugated and unconjugated estrogens and their correlated impurities. The column effluents were subjected on-line to UV irradiation (254 nm) and the photo induced modifications were useful for the identification of the various estrogens. The proposed HPLC methods were successfully applied to the analysis of commercially available conjugated estrogens (raw materials and pharmaceuticals) and estrogen samples. The assays results relative to the pharmaceutical formulations were in agreement with those obtained by a reference HPLC method with UV detection (lambda = 280 nm).