Fasting Study of Letrozole Tablets 2.5 mg and Femara® Tablets 2.5 mg

Inclusion criteria

• Age: 40 years or older.
• Sex: Females only.
• Weight: At least 52 kg (115 lbs) and within 30% of Ideal Body Weight (IBW), as referenced by the Table of ""Desirable Weights of Adults"" from Metropolitan Life Insurance Company, 1999 (See Part II: ADMINISTRATIVE ASPECTS OF HUMAN BIOAVAILABILITY PROTOCOLS).
• Absence of menses for one year for postmenopausal subjects, or at least 6 weeks for oophorectomized subjects. (For oophorectomized subjects, an operative report documenting bilateral oophorectomy and surgical pathology report documenting the absence of malignant disease.)
• Baseline FSH and 17β-estradiol serum levels consistent with postmenopausal status confirmed within 72 hours of initiation of study medication (FSH greater than or equal to 40 mIU/mL; 17β-estradiol less than or equal to 31 pg/mL).
• All subjects should be judged normal and healthy during a pre-study medical evaluation (physical examination, laboratory evaluation, 12-lead ECG, Hepatitis B, Hepatitis C and HIV tests, and urine drug screen including amphetamine, barbiturates, benzodiazepines, cannabinoid, cocaine, opiates, phencyclidine, and methadone) performed within 21 days of the initial dose of study medication.
• The physical examination shall include pelvic and breast exams.

• Pelvic findings should be consistent with hypoestrogenemia.
• A mammogram will be required if not performed within the last 12 months.
• A Papanicolaou ("Pap") smear will be required on subjects with an intact uterus and cervix if not performed within the last 6 months.

Exclusion criteria

• Institutionalized subjects will not be used.
• Social Habits:

• Use of any tobacco-containing products within 1 year of start of study.
• Ingestion of any alcoholic, caffeine- or xanthine-containing food or beverage within the 48 hours prior to the initial dose of study medication.
• Ingestion of any vitamins or herbal products within 7 days prior to the initial dose of the study medication.
• Any recent, significant change in dietary or exercise habits.
• A positive test for any drug included in the urine drug screen.
• History of drug and/or alcohol abuse.
• Medications:

• Use of any prescription or over-the-counter (OTC) medications within the 14 days prior to the initial dose of study medication.
• Use of any medication known to alter hepatic enzyme activity within 28 days prior to the initial dose of study medication.
• Use hormonal replacement therapy within 3 months prior to the initial dose of study medication.
• Diseases:

• History of any significant chronic disease such as (but not limited to): 1. Thrombotic disorders. 2. Coronary artery or cerebrovascular disease. 3. Liver, kidney or gallbladder dysfunction/disorder(s). 4. Diabetes or any other endocrinological disease. 5. Estrogen-dependent neoplasia. 6. Postmenopausal uterine bleeding. 7. Endometrial hyperplasia.
• Acute illness at the time of either the pre-study medical evaluation or dosing.
• A positive HIV, Hepatitis B, or Hepatitis C test.
• Abnormal and clinically significant laboratory test results:

• Clinically significant deviation from the Guide to Clinically Relevant Abnormalities (See Part II ADMINISTRATIVE ASPECTS OF BIOEQUIVALENCE PROTOCOLS).
• Abnormal and clinically relevant ECG tracing.
• Donation or loss of a significant volume of blood or plasma (> 450 mL) within 28 days prior to the initial dose of study medication.
• Subjects who have received an investigational drug within 30 days prior to the initial dose of study medication.
• Allergy or hypersensitivity to letrozole, any of the inactive ingredients.
• History of difficulties in swallowing, or any gastrointestinal disease which could affect the drug absorption.
• Consumption of grapefruit or grapefruit containing products within 7 days of drug administration.