Male/Female subjects, aged 21-45 years inclusive, with a smoking history of at least 20 cigarettes daily (greater than or equal to 50) for at lease 1 year. Subject is in good health as verified by medical history, screening examination, and screening laboratory tests as outlined above. Subject has provided written informed consent to participate in the study and is motivated to stop smoking. Subject has experienced at least 4 withdrawal symptoms upon abstinence.