-Male or female, ages 18 to 45 years, inclusive. -Healthy as determined by screening medical history, medication history, and absence of acute illness such as gastrointestinal or respiratory infection. -Capable of understanding, consenting and complying with the entire study protocol. -Provide voluntary written Informed Consent. -Females of childbearing potential are required to utilize an appropriate method of contraception [abstinence, oral contraceptives, IUD, condoms with spermicidal foam, surgical sterilization depots and injectable contraceptives, or diaphragms with spermicidal jelly or cream] 30 days prior to the Week 12 visit.