Comparative assessment of the absorption of a generic formulation of 5/2.5 mg s 4,5a-epoxy14-hydroxy-3-methoxy-17-methylmorphinan-6-one hydrochloride/naloxone tablet against the innovator 5/2.5 mg s 4,5a-epoxy14-hydroxy-3-methoxy-17-methylmorphinan-6-one hydrochloride/naloxone tablet administered 12 hours apart conducted under fasting conditions and at steady state in healthy volunteers.

Multiple dose, crossover study design whereby each participant receives the test formulation of 5/2.5 mg 4,5a-epoxy14-hydroxy-3-methoxy-17-methylmorphinan-6-one hydrochloride/naloxone tablet on two occasions 12-hours apart, for 2.5 days and the innovator formulation of 5/2.5 mg 4,5a-epoxy14-hydroxy-3-methoxy-17-methylmorphinan-6-one hydrochloride/naloxone tablet 12-hours apart, for 2.5 days on two occasions with each dosing period separated by a 14 day washout period. The intervention for this trial is the test tablet formulation. On study days 1-3 subjects will receive 5 doses 12 hours apart of one formulation (either the test or innovator) and on study days 15-17 they will receive 5 doses 12 hours apart of the other formulation (either the innovator or test). Subjects will be instructed to swallow the medication whole and delegated staff will examine every subject by performing a mouth/hand check to ensure that the medication has been taken as directed. No water is allowed for 1 hour prior to each dosing until 1 hour after dosing (except for water consumed with the dose). Participants are required to fast for at least 4 hours prior to the first four dose administration in each period and at least 8 hours prior to the fifth (last) dose administration in each period. Participants will be confined at the Zenith Clinical Site from at least 1 hour before dosing on Day 1 until after the 12-hour post-dose blood draw on Day 3 for dosing and observation of adverse events, vital sign & pulse oximetry monitoring and the provision of blood samples. Bathroom visits will be supervised to ensure no unauthorised water or food intake and for personal safety. Participants will be confined at the Clinical Site for 1 hour prior to dosing to ensure compliance can be monitored until 12 hours after receiving the final dose (61 hours in each study period). Standard meals will be consumed at the Clinical Site with no additional food intake allowed. Alcohol breath testing and urine DOA testing will be performed upon each participant reporting to the Clinical Site prior to dosing. Pre and post study laboratory tests will be completed to assess the health of participants along with HIV, Hepatitis and drugs of abuse testing.