Bioequivalence of two oral contraceptive drugs containing norethindrone and ethinyl estradiol

Two oral contraceptive drugs, Formulation A and Formulation B, both of similar hormonal content, were compared with each other to determine if they were bioequivalent. Both drugs contain l mg of norethindrone (NET) and 0.035 mg of ethinyl estradiol (EE). Application of an interval test for the ratio of the computed parameter means demonstrated equivalence for the two formulations with respect to the 0–24 hour area under the plasma level versus time curve (AUC 24), the total area under the curve (AUC tot) and for the maximum plasma concentration (C max) for both ethinyl estradiol and norethindrone. The data support the hypothesis for bioequivalence of the two formulations with respect to total absorption.