Stability Indicating-HPLC-DAD method for Determination of Estradiol, Elagolix, and Norethindrone in Pharmaceutical Capsule Dosage Forms

Abstract

In our study, a unique "stability indicating high performance liquid chromatography" (HPLC) approach was developed for the measurement of elagolix, estradiol, and norethindrone concentrations in pharmaceutical capsule dosage forms. The separation was accomplished on a “Waters C18 column” (250 × 4.6 mm, 5 μm). The mobile phase including 0.1 M NaHSO₄ (pH = 4.0) and pure methanol in a volume ratio of 60:40 v/v. The applied flow rate was 1.0 mL/min. The peaks detection and quantification on diode array detector were carried out at 248 nm wavelength. Capsule forms of elagolix, estradiol and norethindrone were exposed to hydrolytic (alkaline and acidic), oxidative, photo and thermal conditions. The retention times for elagolix, estradiol, and norethindrone were 3.206 min, 5.148 min, and 6.823 min, respectively. The proposed stability Indicating-HPLC-DAD approach was validated according to ICH guidelines and showed superior linearity with square of regression coefficient (R²) ˃ 0.999, reliable precision with relative standard deviation in the range of 0.091 to 0.709%, prominent accuracy between 99.130% and 101.323% recoveries and with lowly detection limit (0.008 µg/mL to 0.854 µg/mL) for all analytes. The specificity/stability indicative characteristics of HPLC-DAD approach were proved by peak homogeneity data in the stressed samples peaks acquired from the stressed capsule sample chromatograms. The validated stability Indicating-HPLC-DAD approach can be used for quality control and quality assurance of selected analytes in pharmaceutical oriahnn capsule dosage forms.