Comparing Bioavailability When Preservative-free Makena® (Hydroxyprogesterone Caproate Injection, 250 mg/mL) is Administered as an Intramuscular Manual Injection or as a Subcutaneous Injection Using an Auto-injector in Healthy Post-menopausal Women

Inclusion criteria

• Naturally or surgically postmenopausal women, with or without an intact uterus, aged 50 to 75 years of age, inclusive. FSH levels greater than 40 mIU/mL

Exclusion criteria

• Currently taking any estrogen/progesterone hormone replacement therapy (HRT).
• History of allergy or sensitivity to hydroxyprogesterone caproate, castor oil or any of the constituents of the study medications, or history of any drug hypersensitivity or intolerance
• Poorly controlled diabetes.
• History or current evidence of deep vein thrombosis, pulmonary embolism or arterial thromboembolic disease (e.g., stroke, myocardial infarction).
• Known, suspected, or current history of carcinoma of the breast.
• Subjects with a past history of breast cancer on aromatase inhibitors or selective estrogen receptor modulators.
• Known, suspected, or current history of hormone dependent tumor within the last 5 years.
• Any current or recent (within previous 12 months) genital bleeding of unknown etiology.
• Receipt of any investigational drug within 30 days.
• Receipt of any prescription or OTC medications that are known to alter CYP3A4 or CYP3A5 levels (e.g., carbamazepine, St. John's Wort, ketoconazole, rifampin, ritonavir, alprazolam, azithromycin, loratadine, etc.) within 14.
• Any estrogen, progestin, or selective estrogen receptor modulator (SERM) treatment within specified time windows before the study start, ranging from 2 to 6 months.
• High blood pressure at the screening evaluation, defined as systolic blood pressure > 150 mm Hg or diastolic blood pressure > 90 mm Hg.
• History of excessive alcohol consumption (on average more than 14 units of alcohol/week) during the past 12 months.
• Use of tobacco products within 30 days of the start of the study.