నైరూప్య

Liquid Chromatographic And Spectrophotometric Determination Of Ethinyl Estradiol And Levonorgestrel In Pharmaceutical Preparations

Feyyaz Onur, Ismail Murat Palabiyik

The present work describes a new HPLC method and a new spectrophotometric method for the simultaneous determination of ethinyl estradiol (EE) and levonorgestrel (LNG) in their binary combination. In LC method, Nucleosil C8 column with a mobile phase composed of acetonitrile-water (90:10, v/v) with UV detection at 225 nm were used for the analysis of ethinyl estradiol-levonorgestrel combination. As spectrophotometric method, ratio spectra second derivative spectrophotometry was used. In this method, analytical signals were measured at the wavelengths corresponding to either maximums or minimums for these drugs in the second derivative spectra of the ratio spectra obtained by using each others zero-order spectra as divisor in their solution in methanol in 200-320 nm range. The spectrophotometric procedure does not require any separation step. Linearity range was found as 0.5-60 μg ml-1 for EE and 0.6-60 μg ml–1 for LNG in HPLC method and 1.6-100 μg ml-1 for EE and 2-40 μg ml-1 for LNG in spectrophotometric method. The methods have been validated by analyzing synthetic mixtures containing title drugs and were successfully applied to 2 pharmaceutical formulations, sugar-coated tablets, marketed in Turkey. The results were compared with each other and official method.