Inclusion Criteria includes but is not limited to:
- Body Mass Index (BMI) 18 to 30 and a minimum body weight of 50 kg at screening.
- No history or presence of significant medical condition or a clinically significant abnormal finding, as determined by the investigator.
- Negative urine pregnancy test at screening and baseline for females of childbearing potential
- Agree to refrain from water immersion of the ears from the time of signed informed consent to the end of trial
- Physiologic tympanogram type A (normal) or type C at screening visit
Exclusion Criteria includes but is not limited to:
- Known substance abuse (e.g., alcohol, licit or illicit drugs) within 96 weeks prior to screening visit
- Positive urine drug screen at screening visit
- Upper respiratory tract infection currently or within 6 weeks prior to screening visit
- Allergy or sinus conditions (e.g., sinusitis, non-specific nasal inflammation) currently or within 6 weeks prior to screening visit
- Claustrophobia that is sufficient to prevent them tolerating assessments while in a hypobaric/hyperbaric atmospheric pressure chamber
- Smoker (e.g ., cigarettes, vapor) within the last 48 weeks prior to screening visit
- Clinically significant findings on ear nose and throat exam
- Gastroesophageal reflux disease currently or within 6 weeks prior to screening visit
- Current diagnosis of sleep apnea
- Evidence of craniofacial anomalies (eg, cleft palate, Down's Syndrome) that may interfere with ET function
- Disorders with decreased mucociliary clearance or higher viscosity of the mucous (eg, cystic fibrosis, primary ciliary dyskinesia, Kartagener's syndrome)