This is a single center, two-period, randomized study to evaluate the bioequivalence of a single dose of tasimelteon capsule formulation relative to a single dose of liquid suspension formation in healthy volunteers.

Inclusion Criteria:

• Healthy male and/or female participants between 18 to 55 years (inclusive).
• Good health as determined by no clinically significant deviations from normal in medical history, clinical laboratory determination, ECGs, and physical examinations conducted during the screening visit.
• Participants with no clinically significant medical, psychiatric or sleep disorders as determined by the PI.

Exclusion Criteria:

• Participants with history of drug or alcohol abuse within the 12 months prior to dosing or evidence of such abuse as indicated by the laboratory assays conducted during the screening or baseline evaluations.
• Participants who suffered from significant physical illness (required hospitalization) in the 4-week period preceding baseline will be excluded.
• Participants with history of smoking or use of tobacco products in the last 3 months.
• Pregnant or nursing (lactating) women.