This study will consist of two parts. Double blind Part A will assess the safety, tolerability, and pharmacokinetics of 7 days of dosing in healthy adults, while open label Part B will evaluate the safety, tolerability, and efficacy of a 2-week treatment course in adults with tinnitus.
Healthy male or female adults aged 18 to 64 years (or 65 to 80 years for an elderly cohort, if enrolled), as determined by the investigator.
Able and willing to provide written informed consent and comply with all study procedures.
Body mass index (BMI) 18.0 to 35.0 kilograms per square meter (kg/m²) and body weight greater than (>) 50 kilogram (kg).
Clinically acceptable medical history, physical examination, vital signs, clinical laboratory tests, and 12-lead ECG, as determined by the investigator.
Any clinically significant acute or chronic medical condition that, in the investigator's opinion, could affect participant safety or study assessments.
Use of prohibited medications, including moderate or strong cytochrome (CY)P450 inhibitors or inducers, or other prohibited foods or supplements before dosing.
History of seizures, epilepsy, significant head injury associated with loss of consciousness, or other conditions or medications that increase seizure risk.
Clinically significant cardiovascular disease, clinically significant ECG abnormalities, long QT syndrome, torsade de pointes, or a family history of long QT syndrome or sudden cardiac death.