Study to Assess Pharmacokinetics, Safety, and Tolerability of MT-7117 in Subjects With Normal and Impaired Hepatic Function

Inclusion Criteria:

* Male and female subjects 18 to 75 years of age inclusive
* BMI 18 -35 kg/m2
* If female, you are nonpregnant, non-lactating and willing to utilize approved methods of birth control.

Exclusion Criteria:

* Subjects who have mild or moderate hepatic impairment according to Child-Pugh classification system at Screening (except normal healthy matches)
* Subjects who have a known clinically significant (CS) hypersensitivity to MT-7117 or related compounds, including melatonin.
* Subjects who have previously participated in a study involving MT-7117 or taken any other investigational drug within 30 days or 5 half-lives prior to the first dose of IMP, whichever is longer.
* Subjects who have a CS or unstable neurological, renal, cardiovascular, gastrointestinal, pulmonary, or hematologic disease for 14 days prior to enrollment.
* Subjects who have used any prescription or over-the-counter (OTC) medication within 14 days prior to first dose of IMP, except for occasional use of acetaminophen (\< 1 g/day for normal hepatic subjects, and \< 2 g/day for hepatically impaired subjects) or any other medication approved by the sponsor (a case-by-case basis). For hepatic impaired subjects, prescribed medication or OTC may be permitted by the Investigator and sponsor on a case-by-case basis.