Conjugated estrogens/progestin

This study will compare the bioavailabity of three new investigational combination formulations of Premarin and medroxyprogesterone acetate (MPA) with a currently marketed formulation of Premarin and MPA, Prempro™. Prempro™ is indicated for use after menopause in women with a uterus to reduce moderate to severe hot flashes; to treat moderate to severe dryness, itching, and burning, in and around the vagina; and to help reduce your chances of getting osteoporosis (thin weak bones). The purpose of this study is to determine if these new formulations of Premarin/MPA provide the same levels of estrogen and MPA in the blood as Prempro in healthy postmenopausal women.