- Males or non-pregnant, non-lactating females who are post-menopausal or naturally or surgically sterile (hysterectomy; bilateral oophorectomy; bilateral tubal ligation with surgery at least 6 weeks prior to study initiation). Postmenopausal is defined as at least 12 months natural spontaneous amenorrhea, or at least six weeks following surgical menopause (bilateral oophorectomy). Females of childbearing potential should be using one of the following acceptable birth control methods:Intrauterine device (IUD) in place for at least 3 months;Barrier method (condom or diaphragm) with spermicide; Stable hormonal contraceptive for at least 3 months prior to study and through study completion;Abstinence; Non-heterosexual lifestyle.