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 conducted under fed conditions in healthy volunteers.

INTERVENTION: Single dose, crossover study design whereby each participant receives the test formulation of 1 x 5/2.5 mg 4,5a‐epoxy14‐hydroxy‐3‐methoxy‐17‐methylmorphinan‐6‐one hydrochloride/naloxone tablet on one occasion and the innovator formulation of 1 x 5/2.5 mg 4,5a‐epoxy14‐hydroxy‐3‐methoxy‐17‐methylmorphinan‐6‐one hydrochloride/naloxone tablet on one occasion with each dose separated by a one week washout period. The intervention for this trial is the test tablet formulation. No water is allowed for 1 hour prior to dosing until 1 hour after dosing (except for the water consumed with each dose). Participants are required not to eat for 10 hours before receiving a standardised high fat content meal and to fast for approximately 4 hours after each dose. Bathroom visits will be supervised to ensure no unauthorized water or food intake and for personal safety. Participants will be confined at the Clinical Site for 12 hours prior to dosing to ensure compliance and for 26 hours after dosing. Participants will be monitored for adverse events throughout the study. Standard meals will be consumed at the Clinical Site with no additional food intake allowed. Alcohol breath testing and dipstick drugs of abuse tests will be performed upon each participant reporting to the clinical site 12 hours prior to dosing. Screening and study exit laboratory tests will be completed to assess the health of the participants along with HIV, Hepatitis and drugs of abuse testing. Each dose will be taken orally with 240 ml of water at ambient temperature. Medication must be swallowed whole and a mouth check will be conducted to ensure that the medication has been taken as directed. CONDITION: 5/2.5 mg s 4,5a‐epoxy14‐hydroxy‐3‐methoxy‐17‐methylmorphinan‐6‐one hydrochloride/naloxone belongs to a class of medicines called opioid analgesics and is prescribed for the relief of severe pain.; ; 5/2.5 mg s 4,5a‐epoxy14‐hydroxy‐3‐methoxy‐17‐methylmorphinan‐6‐one hydrochloride/naloxone belongs to a class of medicines called opioid analgesics and is prescribed for the relief of severe pain. Anaesthesiology ‐ Pain management PRIMARY OUTCOME: To evaluate the pharmacokinetics (as summarised by Cmax and AUC) of the test formulation relative to that of the reference formulation. All plasma samples will be assayed for 4,5a‐epoxy14‐hydroxy‐3‐methoxy‐17‐methylmorphinan‐6‐one s using one fully validated LC/MS/MS method. Validation will be conducted to comply with FDA guidelines.[0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 10, 12, 14, 18, 26 and 36 hours post dosing.] SECONDARY OUTCOME: Time to maximum peak concentration (Tmax) will be determined by plasma sample analysis. Tmax will be the time where the maximum concentration occurred in the sample points. ; [0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 10, 12, 14, 18, 26 and 36 hours post dosing] INCLUSION CRITERIA: Healthy males and non‐pregnant females Aged between 18 and 55 years Non‐smoker BMI greater than or equal to 18.5 and less than 32 inclusive Normal, healthy individuals as determined by medical history, physical examination, ECG, blood pressure and laboratory tests Drug free as determined by urine drug testing Able to comply with the study restrictions Able to provide written informed consent