Oral Abuse Potential Study of Nalbuphine

This study will be a single-dose, randomized, double-blind, active- and placebo-controlled, double dummy, 2-part, 7-way crossover study to determine the abuse potential of orally administered nalbuphine solution and nalbuphine ER intact tablets relative to hydromorphone solution and placebo, in non-dependent, recreational opioid users. The study will be conducted in a single clinical research unit (CRU).

The purpose of Part A is to find the appropriate doses (a low, intermediate, and high dose) of nalbuphine solution to use in Part B. Part A of the study has two visits to the research clinic: a screening visit and dose selection visit. The visits will involve a 2-night stay (3 days total) in the research clinic.

In the Main Study Treatment Phase in Part B, the total estimated duration between each dose of study drug is approximately up to 7 days, of which the subject will spend 3 days/2 nights in the research clinic and approximately up to 4 days at home.

The primary objective of the Main Study is to evaluate the abuse potential of orally administered nalbuphine solution and nalbuphine ER intact tablets relative to hydromorphone solution (the active comparator) and placebo in non-dependent, recreational opioid users.

Inclusion criteria

• Healthy male or female subjects 18 to 55 years of age
• Current opioid users who have used opioids for recreational (non-therapeutic) purposes

Exclusion criteria

• Self-reported substance or alcohol dependence (excluding nicotine and caffeine)
• Heavy smoker (≥ 20 cigarettes per day) and/or who is unable to abstain from smoking for at least 8 hours during the in clinic periods.
• History or presence of clinically significant abnormality as assessed by physical examination, medical history, ECGs, vital signs, or laboratory values.
• History or presence of any clinically significant illness
• History of major mental illness that may affect the ability of the subject to participate in the study.