Study Comparing 3 New Formulations of Premarin® 0.625 mg/MPA 2.5 mg With a Reference Formulation

The purpose of this trial is to determine the equivalence of 3 new formulations of a Premarin®/medroxyprogesterone acetate (MPA) combination tablet to the currently marketed dosage form (Prempro® \[TM\]). This study will be performed in healthy postmenopausal women. Each subject will participate in the study for approximately 14 weeks, including a screening evaluation within 3 weeks before the study, and four, 6-day, 5-night inpatient periods with at least a 21-day washout interval between each dose administration.