Single‐Dose Bioequivalence Study of Elagolix Tablets 200 mg (Test Product) and Elagolix Tablets 200 mg (Reference Product) in Healthy Non‐Pregnant, Non‐Lactating Premenopausal Female Subjects Under Fasting Conditions

Elagolix is a short-acting oral gonadotropin-releasing hormone antagonist utilized for treating endometriosis-associated pain by rapidly suppressing gonadotropins and estradiol. Although well characterized in Western populations, clinical data regarding its use in Indian women remain limited. This study evaluated the pharmacokinetics, safety, and bioequivalence of a test 200 mg Elagolix tablet against a reference formulation under fasting conditions. The randomized, open-label, four-period crossover trial involved 60 healthy women aged 18-40 years who received single oral doses of either formulation. Plasma concentrations were monitored via validated UHPLC-MS/MS for 24 h post-dose. Fifty-nine participants completed the study, with results indicating rapid absorption (median T_max 1.25-1.50 h) and a mean half-life of approximately 2.1-2.2 h. Bioequivalence was established as the 90% confidence intervals for key pharmacokinetic parameters-C_max, AUC_0-t, and AUC_0-∞-fell within the regulatory 80%-125% acceptance limits. Specifically, the median AUC_0-t was 3341.23 ng h/mL for the test product compared to 3365.30 ng h/mL for the reference. Both formulations exhibited comparable safety profiles, with only five mild, resolvable adverse events reported. These findings confirm that the test formulation is bioequivalent to the reference standard, supporting its viability as a safe and effective therapeutic alternative.