The purpose of this study is to evaluate the pharmacokinetics of OROS Hydromorphone in healthy adult Taiwanese participants after oral administration of 4 different dose strengths of 8, 16, 32 and 64 mg under fasted conditions.

This is a single-center, randomized (study drug assigned by chance like flipping a coin), open-label (all people involved know the identity of the intervention), 4-way crossover (participants receive different interventions sequentially during the trial) study in healthy adult Taiwanese participants. All participants will be randomly assigned to 1 of the 4 different possible treatment sequences and will receive all treatments in the order specified by the randomization schedule. The study consists of a screening phase, an open-label treatment phase consisting of 4 single-dose treatment periods, and end-of-study or withdrawal assessments. During the open-label treatment periods, the participants will stay in the center until completion of the 72-hour pharmacokinetics [PK] (how the drug is absorbed in the body, distributed within the body, and how it is removed from the body over time) blood sample on Day 4. A 7- to 14-day washout period (period when receiving no treatment) will separate the open-label treatment periods. The safety and tolerability will be evaluated over the investigated dose range. The duration of participation in the study for an individual participant will be approximately 12 weeks.

Inclusion Criteria: - Body mass index (BMI) between 18 and 25 kg/m², inclusive and a body weight of not less than 50 kg - Participants must utilize a medically acceptable method of contraception throughout the entire study period and for 1 month after the study is completed - Each participant will receive a naloxone challenge test for opioid dependency at screening. Only those participants who pass this challenge test will be allowed to continue in the study Exclusion Criteria: - History of or current clinically medical illness or any other condition that the investigator considers should exclude the participant or that could interfere with the interpretation of the study results - Clinically significant abnormal values for hematology, clinical chemistry or urinalysis - Clinically significant abnormal physical examination, vital signs or 12 lead electrocardiogram (ECG) - Use of certain prescription or nonprescription medication, and consumption of products that may interfere with the study