Study of Nalbuphine ER in Participants With Hepatic Impairment

Inclusion Criteria: For participants with Hepatic Impairment (Cohort 1 to 4 and Cohort 6): * Male or female with stable hepatic impairment, non-smoker and/or light smoker. * Clinical diagnosis of liver cirrhosis * Stable for study participation based upon medical history, physical examination, vital signs, ECGs, and screening clinical laboratory evaluations For Healthy participants (Cohort 5): * Male or female, non-smoker and/or light smoker (up to 5 cigarettes or equivalent/day) * Healthy as defined by: * Normal hepatic function * The absence of clinically significant illness and surgery within 4 weeks prior to dosing. Exclusion Criteria: For participants with Hepatic Impairment (Cohort 1 to 4 and Cohort 6): * Clinically significant unstable medical conditions * Clinically significant abnormalities of laboratory, ECG, pulse oximetry, or clinical data that would preclude participation in the study. * History of any illness that might confound the results of the study or pose an additional risk to the participant by participation in the study. For Healthy participants (Cohort 5): * Diagnosis of liver disease * History of heart problems. * History of significant alcohol abuse or drug abuse