A study to assess bioavailability of a single dose of MR902 and to assess the effect of food on absorption

Volunteers will receive a single dose of the investigational drug on 2 occasions and a reference drug on 1 occasion. Volunteers will be randomised to one of two groups, each group receiving a different dose strength of MR902 in fed and fasted state.

The study involves a screening visit 21 days before first dosing and 3 overnight stays in 3 study periods, and a post-study medical visit.

Volunteers will receive naltrexone to reduce anticipated opioid side effects.

Inclusion Criteria:

• Healthy and free of significant abnormal findings as determined by medical history, physical examination, vital signs, laboratory tests and ECG.
• Body weight ranging from 55 to 100 kg and a BMI ≥ 18.5 and ≤ 30.0.
• Willing to eat all the food supplied throughout the study.
• The subject's primary care physician has confirmed within the last 12 months of first dosing that there is nothing in their medical history that would preclude their enrolment into a clinical study.

Exclusion Criteria:

• Female subjects who are pregnant or lactating.
• Any history of drug or alcohol abuse, misuse, physical or psychological dependence.
• Any history of conditions that might interfere with drug absorption, distribution, metabolism or excretion.
• Use of opioid or opioid antagonist-containing medication in the past 30 days.
• Any history of frequent nausea or vomiting regardless of etiology.
• Any history of seizures or symptomatic head trauma.
• History of respiratory depression, hypoxia or elevated carbon dioxide levels in the blood.
• History of paralytic ileus, gastrointestinal disease or other clinically significant gastrointestinal problems.
• Participation in a clinical drug study during the 90 days preceding the initial dose in this study.
• Any significant illness during the 4 weeks preceding entry into this study.
• Use of any medication including vitamins, herbal and/or mineral supplements during the 7 days preceding the initial dose or during the course of this study (with the exception of the continued use of HRT and contraceptives).
• History of smoking within 60 days of IMP administration and refusal to abstain from smoking during the study.