This was a single-center, double-blind, randomized, cross-over Phase 1 study in normal, healthy volunteers. Study treatment entailed single doses of two different formulations of MNTX tablets.

Inclusion Criteria:

1. Weight between 55 and 85 kg
2. In good health, based on history, physical examination, and appropriate laboratory and diagnostic tests at screening, with no evidence of clinically significant chronic medical condition
3. Non-smokers.

Exclusion Criteria:

1. History of evidence of cardiovascular, gastrointestinal, hepatic, musculoskeletal, neurological, pulmonary, renal, or other significant chronic illness
2. History of asthma, allergic skin rash, significant allergy, or other immunologic disorder
3. Consumption of barbiturates or other inducers or inhibitors of CYP450
4. History or suspicion of alcohol or drug abuse.