A Bioavailability Study of NALDEBAIN ER Injection and Nalbuphine Injection in Healthy Volunteers.

Each subject in a cohort will be evaluated for study eligibility during the screening period, which is within 28 days prior to receiving the study drug (Day 1). Eligible subjects will be admitted into the study site on Day -1 and will be required to stay in clinical site for 5 (Cohort 1) or 2 nights (Cohort 2) for study procedures in each cohort. Eligible subjects will undergo additional eligibility assessments on Day -1 and those reconfirmed eligible will intramuscularly receive NALDEBAIN ER Injection (Cohort 1) or nalbuphine (Cohort 2) on Day 1. The blood sampling timepoints for Cohort 1 will be at predose, 6, 12, 24, 48, 56, 64, 72, 80, 88, and 96 hours after dosing. Subjects will be discharged after the 96-hour blood sample and return to the clinical site for the sample collection at 120, 168, 216, 288 and 360 hours post dosing. The blood sampling timepoints for Cohort 2 will be predose, 5, 15, and 30 minutes postdose, and 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours postdose. Subjects will return for a follow-up visit to complete safety evaluations for approximately 15 days after study drug administration in cohort 1; and 1 days after study drug administration in Cohort 2.