Pharmacokinetics, Bioequivalence, and Safety Evaluation of Dienogest in Healthy Subjects Under Fasting and Fed Conditions

Dienogest is effective in reducing endometriosis-related pain symptoms. This study aims to investigate and compare the pharmacokinetic profiles and safety of test formulations to reference formulations of dienogest in healthy Chinese female volunteers under fasting or fed conditions. The purpose of this single-center, randomized, open-label, 2-sequence, 2-period crossover clinical trial was to evaluate the safety and pharmacokinetic profiles of the 2 formulations under fasting and fed conditions. Additionally, 48 healthy female volunteers were selected and divided at random into the fasting and the fed group. After dosing, the venous blood was collected through indwelling catheters. Dienogest plasma concentrations were measured using liquid chromatography-tandem mass spectrometry after the plasma samples were prepared with the protein precipitation method. Under either fasting or fed conditions, the pharmacokinetic parameters (maximum observed concentration, area under the concentration-time curve [AUC] from time 0 to the last measurable concentration, and AUC from time 0 to infinity) for dienogest between the test and reference products, geometric mean ratio, and 90%CI were all within the range of 80%-125%. The 2 dienogest products were bioequivalent. Based on maximum observed concentration and AUC from time 0 to the last measurable concentration, the generic dienogest was bioequivalent to the original dienogest in this study conducted under fasting and fed conditions in healthy Chinese women (study CTR20190063 on registry).