 - Subjects will be in good health as determined by a physical examination and screening laboratory tests and urinalysis, and will meet the criteria of opioid dependence, but will not be physiologically dependent on any other drugs or alcohol; those with history of current binge alcohol use will also be excluded. Subjects will be enrolled in buprenorphine treatment and must be on a stable, standard clinical dose 4-20 mgd for at least 2 weeks prior to initiation of pharmacokinetics study. 